Q5 of 115 Page 8

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

Given,

If (a – 2b) = 30o


∠AOC = a


∠BOC = b


Therefore,


a + b = 180o (i)


Given,


(a – 2b) = 30o (ii)


Now,


Subtracting (i) and (ii), we get


a + b – a + 2b = 180o – 30o


b = 50o


Hence,


(a – 2b) = 30o


a – 2 (50) = 30o


a = 130o


More from this chapter

All 115 →
3

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

 4

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°.

 6

How many pairs of adjacent angles are formed when two lines intersect in a point?

 7

How many pairs of adjacent angles, in all, can you name in Fig. 8.36.