Question

Find the value of x.

Answer 1

∠A=66
∠B=x
∠C=?
∠D=117

Ok, lets sovle for ∠C first.
180-117=∠C
63=∠C

Ok, now we can solve for ∠B or x.
66+63+x=180
129+x=180
-129 -129
x=51

Hope this helps! :)