Question

A semi circle has a radius of 5cm. What is the area of the semi circle?

Use 3.14 for pi.

A.) 15.70
B.) 31.40
C.) 39.25
D.) 78.50

Answer 1

Hello!

We know that the formula for area of a circle is:

A = pi × r^2

A semi circle is half of a circle, which means that its formula would be have of a circles as well.

Formula for area of a semi circle:

A = (pi × r^2) / 2

We'll use the same formula for a semi circle, only we'll divide it by 2 since it's a half circle.

A = (pi × r^2) / 2

A = (3.14 × r^2) / 2

A = 78.5 / 2

A = 39.25

ANSWER:

The area of the semi circle is C.) 39.25 centimetres squared.