Question

The diameter of a circle is 5 kilometers. What is the area?

Answer 1

`\large\boxed{A=6.25\pi\ km^2\approx19.625\ km^2}`

Explanation:

The formula of an area of a circle:

`A=\pi r^2`

r - radius

We have the length of a diameter d = 5 km

We know: d = 2r. Therefor r = 5km : 2 = 2.5 km.

Substitute:

`A=\pi(2.5)^2=6.25\pi\ km^2`

If you want an approximation, then

`\pi\approx3.14\to A\approx(6.25)(3.14)=19.625\ km^2`

Answer 2

Hey!

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Formula: A = πr²

Diameter: d / 2 = r

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Solution:

A = (3.14)(2.5)²

A = (3.14)(6.25)

A = 19.625km.

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Answer:

The area of the circle is 19.625km. or 6.25π km.

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Hope This Helped! Good Luck!