NEED HELP ASAP! Find the measure of the angle(s)

Answer:
x=12
A=36
B=54
C=90
Step-by-step explanation:
x: triangles add up to 180 degrees and c uses up 90 so 5x+30=90* 5x=60* x=12*
A: 2(12)+12
B: 3(12)+18
C: the square in the corner means 90 degrees