Question

Find the area of this semi-circle with radius, r = 78cm.

Give your answer rounded to 1 DP.
********
cm²
r cm
The diagram is not drawn to scale.

Answer 1

Answer: 9556.4 square cm

Solution:
A semicircle is half of a circle. Therefore, to find the area of a semicircle, you can find the area of the circle, then divide that by 2.

The area of a circle is pi * radius squared.

The radius here is 78, so the radius squared will be 6084.

Let’s keep pi as 3.1415. Then the area of the full circle is 6084*3.1415, which is 19112.886.

The semicircle area is half of this, which is 9556.443. Rounded to 1 decimal point, this is 9556.4 square cm.

Answer 2

Explanation:

Whole circle area = pi r^2

Assuming your semicircle is half of this, area = 1/2 pi r^2

area = 1/2 (pi)(78)^2 = 9556 .7 cm^2