Question

A semicircle had an area of 76.97 km squared. Find it's radius

Answer 1

Answer:

$r = 7\ km$

Step-by-step explanation:

The formula for the area of a circle is:

$A = \pi r^2$

Since we know that a semicircle is half of a circle, we can say the area is:

$A = \frac{1}{2}\pi r^2$

From here solve for r:

$76.97 = \frac{1}{2}\pi r^2\\153.94 = \pi r^2\\\frac{153.94}{\pi} = r^2\\r = \sqrt{\frac{153.94}{\pi}}\\r = 7$