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

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10 votes

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

User Alexej Magura
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