Question

how many of these make a semi - circle?
a 1
b 2
c 3
d 4

Explanation:

Step1: Identify the angle of the given shape

The given shape is a quarter - circle, which has an angle of 90 degrees at the center of the circle.

Step2: Identify the angle of a semi - circle

A semi - circle has an angle of 180 degrees at the center of the circle.

Step3: Calculate the number of quarter - circles in a semi - circle

We divide the angle of the semi - circle by the angle of the quarter - circle. Let $n$ be the number of quarter - circles. $n=\frac{180}{90}=2$.

Answer:

B. 2