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If a circle has a circumference of 81 pi what is its radius and area?

User Adp
by
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2 Answers

6 votes

Answer:

Solution :-


\sf Circumference = 2\pi r


\sf \: 81 \pi = 2\pi r


\sf \: 81 = 2r


\sf (81)/(2) = r


\sf \: 40.5 = r

Area = πr²


\sf \: Area = 3.14 * 40.5 * 40.5


\sf \: Area = 5150.38


\sf \: Area = 5150.38 \: units {}^(2)

User ERadical
by
8.4k points
4 votes

Answer:

r = 40.5

A = 1640.25 pi

Explanation:

The circumference is given by

C = pi *d

81 pi = pi *d

Divide each side by pi

81 = d

We can find the radius

d = 2r

81 = 2r

Divide each side by 2

81/2 = r

40.5

Now we can find the area

A = pi r^2

A = pi ( 40.5)^2

A =1640.25 pi

User Arinze
by
7.7k points

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