Q11 of 115 Page 8

In Fig. 8.40, ∠ACB is a line such that ∠DCA = 5x and ∠DCB = 4x. Find the value of x.

∠ACD + ∠BCD = 180^o(Linear pair)

5x + 4x = 180^o

9x = 180^o

x = 20^o

In Fig. 8.38, AOC is a line, find x.

In Fig. 8.39, POS is a line, find x.

Given ∠POR = 3x and ∠QOR = 2x+10, find the value of x for which POQ will be a line.

In Fig. 8.42, a is greater than b by one third of a right angle. Find the values of a and b.