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3 votes
The area of a circle is 49 cm2. Find the circumference of the circle.

(Note: make sure you are showing the formulas you use to answer the question and how the numbers fit into the formulas).

I just need a step by step, please.

User Kaykae
by
5.4k points

2 Answers

4 votes

~Hello There!~

The formula to find the area of a circle is:


\pi r^(2)

We already know this answer, so we write it as:


\pi r^(2) =49

We need to calculate the radius (r) from this so divide both sides by
\pi


r^(2) = 15.59718442

Square root this to get r

r = 3.949327085

The formula for circumference is
\pi *d

(d is the diameter )

Double the radius to get the diameter:

d = 7.89865417

Multiply this value by
\pi to get the answer

The circumference is 24.81435391

Hope This Helps You!

Good Luck :)

Have A Great Day ^_^

- Hannah ❤

User Catgal
by
5.6k points
5 votes

Answer:

C = 14 sqrt(pi)

Explanation:

The formula for area of a circle is

A = pi r^2

49 = pi r^2

Divide each side by pi

49/pi = r^2

Take the square root of each side

sqrt(49/pi) = sqrt(r^2)

sqrt(49/pi) = r

Now we need to find the circumference

C = pi * 2 *r

C = pi * 2 * sqrt(49/pi)

C = pi * 2 *7/sqrt(pi)

We need to get rid of the qrt(pi) in the denominator) so multiply by sqrt(pi)/sqrt(pi)

C = pi * 2 *7/sqrt(pi) * sqrt(pi)/sqrt(pi)

C 14 pi* sqrt(pi)/pi

The pi in the numerator and denominator cancel

C = 14 sqrt(pi)

User LiCheng
by
5.5k points
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