In the given figure, in ΔABC, the angle bisectors of B and C meet at a point O. Find the measure of BOC.

Given, A = 70°

Let the two angles B = 2x and C = 2y.


Then, angle bisector of B, OBC = x and angle bisector of C, OCB = y


A + B + C = 180° [Sum of all angles of a triangle = 180°]


70° + 2x + 2y = 180°


2x + 2y = 110°


x + y = 55° …. (i)


Now,


BOC + x + y = 180° [Sum of all angles of a triangle = 180°]


BOC = 180° - (x + y)


BOC = 180° - 55° [from eq. (i)]


BOC = 125°


20