I will give you a Brainly crown if it is right. Will you help me plzzzzzz helplpppppp

Answer:
90
Step-by-step explanation:
A semicircle is 1/2 of a circle
A circle is 360 degrees
1/2 is 180
We have 90 degrees already used on the left
180-90 = 90
b = 90 degrees
Answer:
90
Step-by-step explanation:
The whole thing equals 360
so have equals 180
and half of one 180 is 90 and you're trying to find that half of 180.