Question

in triangle abc the angle bisectors of Angle B and C meet at O if angle a = 70 degree find angle BOC

Answer 1

This is how you do it.
Hope that helps you.

Answer 2

In triangle ABC

Using Angle Sum Property, angleA + angleB + angleC = 180

Since angleA = 70, angleB + angleC = 110 →(i)

In triangle BOC

Using Angle Sum Property, angleBOC + angleOCB + angleOBC = 180

angleBOC + 1/2angleC + 1/2angleB = 180

angleBOC + 1/2(angleC + angleB) = 180

angleBOC + 1/2(110) = 180

angleBOC = 180-55

angleBOC = 125

Alter method: Using Corrolary of Angle Sum Property

angleBOC = 90 + 1/2angleA

angleBOC = 90 + 35

angleBOC = 125