Question

A circle has an area of 441π cm2. What is the circumference

Answer 1

area = pi r^2

441pi = pi r^2
r^2 = 441
r = sqrt(441)

circumference= 2pi r
circumfrence = 2 pi (sqrt 441)

Hope this helps!

Answer 2

\[A =\pi r^2\]

\[C = 2\pi r\]

\[441 = \pi r^2\]

Answer 3

Solve for r, then use it to find C.

Answer 4

Or nvm, I guess bob solved it for ya.

Answer 5

a.

21π cm

c.

42 cm


b.

42π cm

d.

21 cm

Answer 6

You have everything you need, you can solve it now :)