Find the measure of A in the picture below.

Step-by-step explanation:

If you draw in BD, you can show that triangle BCD = triangle BAD by SSS

That means that <A = <C  parts of congruent parts are congruent.

<A + <C + 115 + 71 = 360

<A + <C + 186 = 360            All convex quadrilaterals have  4 interior angles that add to  360 degrees

<A + <C = 360 - 186

<A + <C = 174

So call <A  and < C = x

x + x = 174

2x = 174

x = 174 / 2

x = 87

<A = 87

unless if u could do my questions, if not i wouldn't want to

the answer is c: divide the arc's degree measure by 360°, then multiply by the circumference of the circle.