Q9 of 115 Page 8

In Fig. 8.61, lines AB, CD and EF intersect at O. Find the measures of ∠AOC, ∠COF, ∠DOE and ∠BOF.

∠AOE + ∠EOB = 180o(Linear pair)

∠AOE + ∠DOE + ∠BOD = 180o


∠DOE = 105o


∠DOE = ∠COF = 105o(Vertically opposite angle)


∠AOE + ∠AOF = 180o(Linear pair)


40o + ∠AOC + 105o= 180o


∠AOC = 35o


Also,


∠BOF = ∠AOE = 40o(Vertically opposite angle)


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In Fig. 8.60, ray AB and CD intersect at O.


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