Question

find the area of the semicircle.
13.
14.
15.
40 cm
24 in.
2 ft

Explanation:

Step1: Find radius of semicircle 13

The diameter is 40 cm, so radius $r_1 = \frac{40}{2} = 20$ cm.

Step2: Calculate area of semicircle 13

Area formula for semicircle: $\frac{1}{2}\pi r^2$.
$\text{Area}_1 = \frac{1}{2} \pi (20)^2 = 200\pi \approx 628$ cm²

Step3: Find radius of semicircle 14

The diameter is 24 in, so radius $r_2 = \frac{24}{2} = 12$ in.

Step4: Calculate area of semicircle 14

$\text{Area}_2 = \frac{1}{2} \pi (12)^2 = 72\pi \approx 226.08$ in²

Step5: Find radius of semicircle 15

The diameter is 2 ft, so radius $r_3 = \frac{2}{2} = 1$ ft.

Step6: Calculate area of semicircle 15

$\text{Area}_3 = \frac{1}{2} \pi (1)^2 = \frac{1}{2}\pi \approx 1.57$ ft²

Answer:

1. $200\pi$ cm² (or approximately 628 cm²)
2. $72\pi$ in² (or approximately 226.08 in²)
3. $\frac{1}{2}\pi$ ft² (or approximately 1.57 ft²)