Showing posts with label Parallelograms. Show all posts
Showing posts with label Parallelograms. Show all posts

S.chand Class 8 Maths Solution Chapter 13 Parallelograms Exercise 13 B

 Exercise 13 B

Question 1

1. For each of the statements given below, indicate if it is true (T) or false $(F)$ :

(a) A rectangle is a parallelogram.

(b) A square is a rectangle.

(c) A parallelogram is a rhombus.

(d) A square is a rhombus.

(e) A rectangle is a square.

(f) A square is a parallelogram.


2. What kind of quadrilateral is formed when the mid points of the sides of the following are joined?

(a) a rectangle,

(b) a rhombus,

(c) a kite,

(d) an isosceles trapezium.


3. $A B C D$ is a rectangle, $E F G H$ is a rhombus and $P Q R S$ is a square.


Complete the followings :

(i) $F H \perp $ ___

(ii) $G E$ bisects ___

(iii) If $\angle F E H=130^{\circ}, \angle E H G=$ ___

(iv) If $A C=4, B D=$ ___

(v) If PQ=4, PS=___

(vi) If $\angle E H G=48^{\circ}, \angle H G O=$ ___

(vii) If $H E=12, G H=$ ___

(viii) $\angle E O F=$ ___


4. The diagonals of a rectangle $A B C D$ intersect at $O$. If $\angle B O C=44^{\circ}$, find $\angle O A D$.

5. $A B C D$ is a rhombus with $\angle A B C=56^{\circ}$. Determine $\angle C A D$.

<fig>


6. $A B C D$ is a rhombus. If $\angle D A C=50^{\circ}$, find 

(a) $\angle A C D$

(b) $\angle C A B$

(c) $\angle A B C$.


7. $A B C D$ is a trapezium in which $A B \| D C$. If $\angle A=\angle B=40^{\circ}$, what are the measures of the other two angles?


8. Calculate the angles marked with small letters in the following diagrams.

<fig>


9. $A B C D$ is a kite. If $\angle B C D=40^{\circ}$, find (a) $\angle B D C$ (b) $\angle A B C$.

<fig>


10. $A B C D$ is a trapezium and $A B E D$ is a square. If $B E=E C$, find: (a) $\angle B A E$

(b) $\angle A B C$

(c) What shape is the figure $A B C E$ ?


11. $A B C D$ is a square and $A B R S$ is a rhombus. If $\angle S A D=120^{\circ}$, find: (a) $\angle A S D \quad$ (b) $\angle S R B$.


12. $A B C D$ is a kite and $\angle A=\angle C$. If $\angle C A D=70^{\circ}, \angle C B D=65^{\circ}$, find : (a) $\angle B C D$ (b) $\angle A D C$.


13. If the diagonals of a rhombus are $12 \mathrm{~cm}$ and $16 \mathrm{~cm}$, find the length of each side.


Multiple Choice Questions (MCQs)


14. What value of $x$ makes the given parallelogram a square ?

(a) $7.5^{\circ}$

(b) $6.5^{\circ}$

(c) $4.5^{\circ}$

(d) $8.5^{\circ}$


15. Quadrilateral $A B C D$ is a kite. What is the length of the line segment $A E$ ?

(a) $4 \mathrm{~cm}$

(b) $6 \mathrm{~cm}$

(c) $5 \mathrm{~cm}$

(d) $13 \mathrm{~cm}$


16.$C D E F$ is a square. Find $x$.

(a) $142^{\circ}$

(b) $92^{\circ}$

(c) $113^{\circ}$

(d) $83^{\circ}$




S.chand Class 8 Maths Solution Chapter 13 Parallelograms Exercise 13 A

 Exercise 13 A

Question 1

1. The measure of one angle of a parallelogram is $80^{\circ}$. What are the measures of the remaining angles ?

2. Two adjacent angles of a parallelogram are congruent. What is the measure of each?

3. Two adjacent sides of a parallelogram are $5 \mathrm{~cm}$ and $6 \mathrm{~cm}$ respectively. Find its perimeter.

4. Find each angle of a parallelogram if two consecutive angles are in the ratio $1: 3$.

5. The perimeter of a parallelogram is $180 \mathrm{~cm}$. One of its sides is greater than the other by $30 \mathrm{~cm}$. Find the length of the sides of the parallelogram.

6. Find the sizes of the angles of a parallelogram if one angle is $20^{\circ}$ less than twice the smallest angle.

7. $A B C D$ is a parallelogram. Find $x, y$ and $z$.

8. In the figure, find the four angles $A, B, C$ and $D$ of the parallelogram $A B C D$.

9. $A B C D$ is a parallelogram. $C E$ bisects $\angle C$ and $\mathrm{AF}$ bisects $\angle A$. In each of the following, if the statement is true, give a reason for the same.

(i) $\angle A=\angle C$

(ii) $\angle F A B=\frac{1}{2} \angle A$

(iii) $\angle D C E=\frac{1}{2} \angle C$.

(iv) $\angle F A B=\angle D C E$

(v) $\angle D C E=\angle C E B$

(vi) $\angle C E B=\angle F A B$

(vii) $C E \| A F$

(viii) $A E \| F C$.


Multiple Choice Questions (MCQs)


10. If the quadrilateral $\mathrm{ABCD}$ is a parallelogram. What is the value of $x$ ?

(a) $45^{\circ}$

(b) $30^{\circ}$

(c) $36^{\circ}$

(d) $37^{\circ}$


11. What values of a would make the given quadrilateral a parallelogram.

(a) $5 \frac{1}{4}$

(b) $5 \frac{1}{2}$

(c) $5 \frac{3}{4}$

(d) 5


High Order Thinking Skills (HOTS)

12. The diagonal of a rectangle is thrice its smaller side. Find the ratio of its sides.

[Hint. Use Pythagoras theorem]

(a) $\sqrt{2}: 1$

(b) $2 \sqrt{2}: 1$

(c) $3: 2$

(d) $\sqrt{3}: 1$








RS Aggarwal solution class 8 chapter 16 Parallelograms Exercise 16B

Exercise 16B

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Q1 | Ex-16B | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 1:

Tick (✓) the correct answer
The two diagonals are not necessarily equal in a
(a) rectangle
(b) square
(c) rhombus
(d) isosceles trapezium

Answer 1:

(c) rhombus In a rhombus, the two diagonals are not necessarily equal.


Q2 | Ex-16B | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 2:

Tick (✓) the correct answer
The lengths of the diagonals of a rhombus are 16 cm and 12 cm. The length of each side of the rhombus is
(a) 8 cm
(b) 9 cm
(c) 10 cm
(d) 12 cm

Answer 2:

(c) 10 cm


      



           


Let ABCD be a rhombus.Let AC and BD be the diagonals of the rhombus intersecting at a point O.AC=16 cm BD=12 cmWe know that the diagonals of a rhombus bisect each other at right angles. AO=12AC     =12×16 cm     =8 cmBO=12BD      =12×12 cm      =6 cmFrom the right AOB:AB2=AO2+BO2       =82+62 cm2       =64+36 cm2       =100 cm2AB=100 cm          =10 cmHence, the length of the side AB is10 cm.Therefore, the length of each side of the rhombus is 10 cm because all the sides of a rhombus are equal.


Q3 | Ex-16B | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 3:

Tick (✓) the correct answer
Two adjacent angles of a parallelogram are (2x + 25)° and (3x − 5)°. The value of x is
(a) 28
(b) 32
(c) 36
(d) 42

Answer 3:

(b) 32We know that the sum of adjacent angles of a parallelogram is180°.2x+25+3x-5=1805x+20=1805x=180-205x=160x=1605x=32Therefore, the value of x is 32.


Q4 | Ex-16B | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 4:

Tick (✓) the correct answer:
The diagonals do not necessarily intersect at right angles in a
(a) parallelogram
(b) rectangle
(c) rhombus
(d) kite

Answer 4:

(a) parallelogramIn a parallelogram, the diagonals do not necessarily intersect at right angles.


Q5 | Ex-16B | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 5:

Tick (✓) the correct answer:
The length and breadth of a rectangle are in the ratio 4 : 3. If the diagonal measures 25 cm then the perimeter of the rectangle is
(a) 56 cm
(b) 60 cm
(c) 70 cm
(d) 80 cm

Answer 5:

(c) 70 cm

Let ABCD be a rectangle and let the diagonal AC be 25 cm, length AB be 4x cm and breadth BC be 3x cm.Each angle of a rectangle is a right angle.ABC=90°From the right ABC:AC2=AB2+BC2252=4x2+3x2625=16x2+9x2625=25x2

x2= 62525=25x=5 Length =4×5=20 cmBreadth=3×5=15 cm 

∴ P
erimeter of the rectangle = 2(20+15) cm
                                         =70 cm


Q6 | Ex-16B | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 6:

Tick (✓) the correct answer:
The bisectors of any two adjacent angles of a parallelogram intersect at
(a) 30°
(b) 45°
(c) 60°
(d) 90°

Answer 6:

(d) 90°The bisectors of any two adjacent angles of a parallelogram intersect at 90°.


Q7 | Ex-16B | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 7:

Tick (✓) the correct answer:
If an angle of a parallelogram is two-thirds of its adjacent angle, the smallest angle of the parallelogram is
(a) 54°
(b) 72°
(c) 81°
(d) 108°

Answer 7:

(b) 72°Let x° be the angle of the parallelogram. Sum of the adjacent angles of a parallelogram is 180°.  x+23×x=180x+2x3=180x+2x3=1805x3=180x=180×35x=108Hence, one angle of the parallelogram is 108°.Its adjacent angle = 180-108°=72°Therefore, the smallest angle of the parallelogram is 72°.


Q8 | Ex-16B | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 8:

Tick (✓) the correct answer:
The diagonals do not necessarily bisect the interior angles at the vertices in a
(a) rectangle
(b) square
(c) rhombus
(d) all of these

Answer 8:

(a) rectangle In a rectangle, the diagonals do not necessarily bisect the interior angles at the vertices.


Q9 | Ex-16B | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 9:

Tick (✓) the correct answer:
In a square ABCD, AB = (2x + 3) cm and BC = (3x − 5) cm. Then, the value of x is
(a) 4
(b) 5
(c) 6
(d) 8

Answer 9:

(d) 8All the sides of a square are equal.AB=BC2x+3=3x-53+5=3x-2x8=xTherefore, the value of x is 8. 


Q10 | Ex-16B | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 10:

Tick (✓) the correct answer:
If one angle of a parallelogram is 24° less than twice the smallest angle then the largest angle of the parallelogram is
(a) 68°
(b) 102°
(c) 112°
(d) 176°

Answer 10:

(c) 112°Let x° be the smallest angle of the parallelogram.The sum of adjacent angles of a parallelogram is 180°. x+2x-24=1803x-24=1803x= 180+243x=204x=2043x=68 Smallest angle=68°Largest angle = 180-68°=112°

RS Aggarwal solution class 8 chapter 16 Parallelograms Exercise 16A

Exercise 16A

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Q1 | Ex-16A | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 1:

ABCD is a parallelogram in which ∠A = 110°. Find the measure of each of the angles ∠B,C and ∠D.

Answer 1:

It is given that ABCD is a parallelogram in which A is equal to 110°.Sum of the adjacent angles of a parallelogram is 180°.  A+B=180°110°+ B=180°B=180°-110°B=70° B=70°

Also, B+C=180°70°+C=180°C=180°-70°C=110° C=110°Further, C+D=180°110°+D=180°D=180°-110°D=70° D=70°


Q2 | Ex-16A | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 2:

Two adjacent angles of a parallelogram are equal. What is the measure of each of these angles?

Answer 2:

Let the required angle be x°.As the adjacent angles are equal, we have:    x+x=180            since the sum of adjacent angles of a parallelogram is 180°2x=180x=1802x=90°Hence, the measure of each of the angles is 90°.

Q3 | Ex-16A | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 3:

Two adjacent angles of a parallelogram are in the ratio 4 : 5. Find the measure of each of its angles.

Answer 3:






 Let ABCD be the parallelogram.Then, A and B are its adjacent angles.Let A=4x° B=5x°   A+B=180°      since sum of the adjacent angles of a parallelogram is 180°4x+5x=1809x=180x=1809x=20 A=4×20°=80°      B=5×20°=100°Opposite angles of parallelogram are equal. C=A=80°D=B=100°                                

Q4 | Ex-16A | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 4:

Two adjacent angles of a parallelogram are (3x − 4)° and (3x + 16)°. Find the value of x and hence find the measure of each of its angles.

Answer 4:








Let ABCD be a parallelogram.Let A=3x-4° B=3x+16°   A+B=180°       since the sum of adjacent angles of a parallelogram is 180°3x-4+3x+16=1803x-4+3x+16=1806x+12=1806x=168x=1686x=28 A=3×28-4°       =84-4°       =80°B=3×28+16°       =84+16°       =100°The opposite angles of a paralleleogram are equal.C=A=80°D=B=100°

Q5 | Ex-16A | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 5:

The sum of two opposite angles of a parallelogram is 130°. Find the measure of each of its angles.

Answer 5:






Let ABCD be a parallelogram and let the sum of its opposite angles be 130°. A+C=130°The opposite angles are equal in a parallelogram.      A=C=x°x+x=1302x=130x=1302x=65A=65° and C=65°    A+B=180°       since the sum of adjacent angles of a parallelogram is 180°65°+B=180°B=180-65°B=115°D=B=115°           [opposite angles of parallelogram are equal]


Q6 | Ex-16A | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 6:

Two sides of a parallelogram are in the ratio 5 : 3. If its perimeter is 64 cm, find the lengths of its sides.

Answer 6:

Let the lengths of two sides of the parallelogram be 5x cm and 3x cm, respectively.Then, its perimeter =25x+3x cm
                             =16x cm
   16x=64x=6416x=4 One side5×4 cm=20 cmOther side3×4 cm=12 cm


Q7 | Ex-16A | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 7:

The perimeter of a parallelogram is 140 cm. If one of the sides is longer than the other by 10 cm, find the length of each of its sides.

Answer 7:

Let the lengths of two sides of the parallelogram be x cm and  x+10 cm, respectively.Then, its perimeter =2[x+x+10] cm
                           
                         =2[x+x+10] cm=2[2x+10] cm=4x+20 cm

     4x+20=1404x=140-204x=120x=1204x=30Length of one side=30 cm Length of the other side30+10 cm=40 cm


Q8 | Ex-16A | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 8:

In the adjacent figure, ABCD is a rectangle. If BM and DN are perpendiculars from B and D on AC, prove that ∆BMC ≅ ∆DNA. Is it true that BM = DN?








Answer 8:

Refer to the figure given in the book.

In BMC and DNA:DNA=BMC=90°BCM=DAN     alternate anglesBC=DA     opposite sidesBy AAS congruency criteria: BMCDNAYes, it is true that BM is equal to DN.     by corresponding parts of congruent triangles BMC and DNA 


Q9 | Ex-16A | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 9:

In the adjacent figure, ABCD is a parallelogram and line segments AE and CF bisect the angles A and C respectively. Show that AE||CF.








Answer 9:

Refer to the figure of the book.

A=C                                        opposite angles of a parallelogram are equal12A=12C=>EAD=FCB                  (AE and CF bisect the angles A and C, respectively) In ADE and CBF:B=D                                      opposite angles of a parallelogram are equalEAD=FCB                          (proved above)  AD=BC                                      opposite sides of a parallelogram are equalBy AAS concruency criteria: ADEBCFDE=BF                                     (corresponding parts of congruent triangles)CD=AB                                   opposite sides of a parallelogram are equal       Also, CD-DE=AB-BFCE=AFABCD is a paralleleogram.  CDAB                           (opposite sides of a parallelogram are parallel)=>CE AF If one pair of sides of a quadrilateral is parallel and equal, then it is a parallelogram.Therefore, AECF is a parallelogram. AECF 


Q10 | Ex-16A | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 10:

The lengths of the diagonals of a rhombus are 16 cm and 12 cm respectively. Find the length of each of its sides.

Answer 10:







Let ABCD be a rhombus.Let AC and BD be the diagonals of the rhombus intersecting at a point O.Let AC=16 cm BD=12 cmWe know that the diagonals of a rhombus bisect each other at right angles.AO=12AC     =12×16 cm     =8 cmBO=12BD      =12×12 cm      =6 cmFrom the right AOB:AB2=AO2+BO2       =82+62 cm2       =64+36 cm2       =100 cm2AB=100 cm          =10 cmHence, the length of the side AB is10 cm.AB=BC=CD=DA=10 cm               (all sides of a rhombus are equal)


Q11 | Ex-16A | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 11:

In the given figure ABCD is a square. Find the measure of ∠CAD.









Answer 11:

Refer to the figure given in the book.

In ADC:DA=DC                 (all sides of a square are equal) ACD=CADLet ACD=CAD=x°     [Angle opposite to the equal sides are equal]x+x+90=180                     since the sum of the angles of a triangle is 180°2x+90=1802x=90x=902x=45 CAD=45°


Q12 | Ex-16A | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 12:

The sides of a rectangle are in the ratio 5 : 4 and its perimeter is 90 cm. Find its length and breadth.

Answer 12:

Let the length of two sides of the rectangle be 5x cm and 4x cm, respectively.Then, its perimeter=25x+4x cm
                            =18x cm
  18x=90x=9018x=5Length of one side5×5 cm=25 cmLength of the other side4×5 cm=20 cmLength of the rectangle=25 cm Breadth=20 cm


Q13 | Ex-16A | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 13:

Name each of the following parallelograms.
(i) The diagonals are equal and the adjacent sides are unequal.
(ii) The diagonals are equal and the adjacent sides are equal.
(iii) The diagonals are unequal and the adjacent sides are equal.
(iv) All the sides are equal and one angle is 60°.
(v) All the sides are equal and one angle is 90°.
(vi) All the angles are equal and the adjacent sides are unequal.

Answer 13:

i The diagonals are equal and the adjacent sides are unequal.      Hence, the given parallelogram is a rectangle.ii The diagonals are equal and the adjacent sides are equal.      Hence, the given parallelogram is a square.iii The diagonals are unequal and the adjacent sides are equal.        Hence, the given parallelogram is a rhombus.iv All the sides are equal and one angle is 60°.       Hence, the given parallelogram is a rhombus.v All the sides are equal and one angle is 90°.      Hence, the given parallelogram is a square.vi All the angles are equal and the adjacent sides are unequal.       Hence, the given parallelogram is a rectangle.


Page-194

Q14 | Ex-16A | Class 8 | RS AGGARWAL | chapter 16 | Parallelograms 

Question 14:

Which of the following statements are true and which are false?
(i) The diagonals of a parallelogram are equal.
(ii) The diagonals of a rectangle are perpendicular to each other.
(iii) The diagonals of a rhombus are equal.
(iv) Every rhombus is a kite.
(v) Every rectangle is a square.
(vi) Every square is a a parallelogram.
(vii) Every square is a rhombus.
(viii) Every rectangle is a parallelogram.
(ix) Every parallelogram is a rectangle.
(x) Every rhombus is a parallelogram.

Answer 14:

i The given statement is false.The diagonals of a parallelogram bisect each other, but they are not equal in length.ii The given statement is false.The diagonals of a rectangle are equal and bisect each other, but they are not perpendicular.iii The given statement is false.All the sides of a rhombus are equal, but the diagonals are not equal.iv The given statement is true.v The given statement is false.Every square is a rectangle, but every rectangle is not a square.vi The given statement is true.vii The given statement is true.viii The given statement is true.ix The given statement is false.A rectangle is a special type of parallelogram, but every parallelogram is not a rectangle.x The given statement is true.

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