## MP Board Class 7th Maths Solutions Chapter 10 Practical Geometry Ex 10.4

Question 1.

Construct ∆ABC, given m ∠A = 60°, m ∠B = 30° and AB = 5.8 cm.

Solution:

Steps of Construction :

1. Draw a line segment AB if 5.8 cm length.

2: Draw ∠BAX = 60°.

3. Draw ∠ABY = 30°.

4. Let AX and BY intersect at A.

Then, ABC is the required triangle.

Question 2.

Construct ∆PQR if PQ = 5 cm, m ∠PQR = 105° m ∠QRP = 40°.

Solution:

Here, ∠Q, ∠R and the side PQ are given. But to draw. We know that,

∠P + ∠Q + ∠R = 180° (∵ Sum of the angles of a triangle is 180°)

or ∠P + 105° + 40° = 180°

or ∠P = 180° – 145° = 35°

Thus, we have PQ = 5 cm,

∠P = 35° and ∠Q = 105°.

Steps of Construction :

1. Draw a line segment PQ if 5 cm length.

2: Draw ∠QPX = 35°.

3. Draw ∠PQY = 105°.

4. Let PX and QY intersect at R.

Then, PQR is the required triangle.

Question 3.

Examine whether you can construct ∆DEF such that EF = 7.2 cm, m ∠E = 110° and m ∠F = 80°. Justify your answer.

Solution:

Given, m∠E = 110° and m∠F = 80°

Since, m ∠E + m∠E = 110° + 80° = 190° > 180°

Thus, the ∆DEF cannot be drawn.