Question

Find the value of a in the picture

Answer 1

The measure of arc a is 86°

Explanation:

we know that

The measure of the inner angle is the semi-sum of the arcs comprising it and its opposite.

so

86°=(1/2)[arc c+arc a]

see the attached figure with letters to better understand the problem

In this problem

Triangles ABO and CDO are congruent by SSS postulate theorem

∠AOB=∠COD

∠AOB=arc a -----> by central angle

∠COD=arc c -----> by central angle

therefore

The measure of arc a is congruent with the measure of arc c

arc a=arc c

so

86°=(1/2)[2arc a]

86°=[arc a]

arc a=86°