Quadrilateral abcd is inscribed in a circle.

what is the measure of angle a?

enter your answer in the box.

m∠a=

One of the circle theorems is that opposite angles in a cyclic quadrilateral sum to 180°.
So, m<A + m<C = 180°. Let's substitute:
3x+6+x+2=180
4x+8=180
4x=172
x=43°
m<A = 3x + 6
m<A = 3(43)+6
m<A = 129+6
m<A = 135°

The first option would be correct if it were one half and not one