Answer:
Use the formula for the trapeze
Step-by-step explanation:
∠ C = 88°
The opposite angles in a cyclic quadrilateral sum to 180°, then
8x - 4 + 7x + 4 = 180 , that is
15x = 180 ( divide both sides by 15 )
x = 12
Then
∠ C = 7x + 4 = 7(12) + 4 = 84 + 4 = 88°
