Question

If O is the centre of the circle, find the value of x in each of the following figures

Answer 1

In BOC,
OB = OC                           ...(radii)
So, OCB = OBC = 40°

In BOC,
BOC = 180° - (40° + 40°)
BOC = 180° - 80°
So, 
x = `"BOC"/2`

x = `(100°)/2` = 50°.