1 Answer

Alexej Magura · Answer 1 · 2023-09-10T12:01:53+0000

Answer:

$r = 7\ km$

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:

$A = (1)/(2)\pi r^2$

From here solve for r:

$76.97 = (1)/(2)\pi r^2\\153.94 = \pi r^2\\(153.94)/(\pi) = r^2\\r = \sqrt{(153.94)/(\pi)}\\r = 7$

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