Q21 of 158 Page 159

From Fig. 6.10, the value of x is

As exterior angle is equal to sum of opposite interior angle

∴ ∠ACD = ∠A + ∠B

∠ACD = 25° + 35° = 60°

In another triangle

x is exterior angle

∴ x = 60° + ∠ACD

x = 60° + 60° = 120°

In Fig. 6.9, BC = CA and ∠A = 40. Then, ∠ACD is equal to

The length of two sides of a triangle are 7 cm and 9 cm. The length of the third side may lie between

In Fig. 6.11, the value of

∠A + ∠B + ∠C + ∠D + ∠E + ∠F is

In Fig. 6.12, PQ = PR, RS = RQ and ST || QR. If the exterior angle RPU is 140°, then the measure of angle TSR is