Q3 of 115 Page 8

In Fig. 8.33, find x. Further find ∠BOC, ∠COD and ∠AOD.

∠AOD + ∠BOD = 180^o (Linear pair)

∠AOD + ∠COD + ∠BOC = 180^o (Linear pair)

Given that,

∠AOD = (x + 10)

∠COD = x

∠BOC = (x + 20)

(x + 10) + x + (x + 20) = 180⁰

3x = 150^o

x = 50^o

Therefore,

∠AOD = 60^o

∠COD = 50^o

∠BOC = 70^o

In Fig. 8.31, OA and OB are opposite rays:

(i) If x = 25°, what is the value of y?

(ii) If y = 35°, what is the value of x?

In Fig. 8.32, write all pairs of adjacent angles and all the linear pairs.

In Fig. 8.34, rays OA, OB, OC, OD and OE have the common end point O. Show that ∠AOB +∠BOC +∠COD +∠DOE + ∠EOA = 360°.

In Fig. 8.35, ∠AOC and ∠BOC form a linear pair. If a -2b = 30°, find a and b.