RS Aggarwal 2019,2020 solution class 7 chapter 17 Construction Exercise 17A

Exercise 17A

Page-204

Question 1:

Draw a line AB and take a point P outside it. Draw a line CD parallel to AB and passing through the point P.

Answer 1:

$$\begin{gathered} \begin{array}{l}\text{Steps of construction:}\\ 1.\mathrm{Draw} \mathrm{a} \mathrm{line} \mathrm{AB}.\end{array} \\ \begin{array}{l}2. \text{Take a point Q on AB and a point P outside AB, and join PQ.}\\ \text{3. With Q as the centre and any radius, draw on arc to cut AB at X and PQ at Z.}\\ \text{4. With P as the centre and the same radius, draw an arc cutting QP at Y .}\\ \text{5. With Y as the centre and the radius equal to XZ, draw an arc to cut the previous arc at E.}\\ \text{6. Join PE and produce it on both the sides to get the required line}\text{.}\end{array} \end{gathered}$$

Question 2:

Draw a line AB and draw another line CD parallel to AB at a distance of 3.5 cm from it.

Answer 2:

$\begin{array}{l}\text{Steps for construction:}\\ 1. \text{Let AB be the given line}\text{.}\\ 2. \text{Take any two points P and Q on AB}\text{.}\\ \text{3}\text{. Construct }\angle BPE=90°\text{ and }\angle BQF=90°\\ 4. \text{With P as the centre and the radius equal to 3}\text{.5 cm, cut PE at R.}\\ \text{5}\text{. With Q as the centre and the radius equal to 3}\text{.5cm, cut QF at S.}\\ \text{6}\text{. Join RS and produce it on both the sides to get the required line, parallel to AB and at a distance of 3}\text{.5 cm from it}\text{.}\\ \\ \end{array}$

Question 3:

Draw a line l and draw another line m parllel to l at a distance of 4.3 cm from it.

Answer 3:

$\begin{array}{l}\text{Steps of construction:}\\ \text{1}\text{. Let}\mathit{\text{ l}}\text{ be the given line}\text{.}\\ \text{2}\text{. Take any two points A and B on line}\mathit{\text{ l.}}\\ 3. \text{Construct }\angle B\text{AE}=90°\text{ and }\angle \text{ABF=90}°\\ 4. \text{With A as the centre and the radius equal to 4}\text{.3 cm, cut AE at C}\text{.}\\ \text{5}\text{. With B as the centre and the radius equal to 4}\text{.3 cm, cut BF at D}\text{.}\\ \text{6}\text{. Join CD and produce it on either side to get the required line m, parallel to l and at a distance of 4}\text{.3 cm from it}\text{.}\\ \\ \end{array}$