One property of cyclic quadrilaterals is that opposite angles add up to 180.
since B and D are opposite angles, we can add them and set that to 180. we get that 5x+5=180, so x=35. Now, substituting 37 for x for all the angles, we get
A=73
B=66
D=114
To find C, notice that A and C are opposite angles. This means they add up to 180
