Question

help me.

Answer 1

Questions here.

Answer 2

The area of a circle is given by \[A =\pi r^2\]
and circumference is
\[C=2 \pi r\]

They both have a radius r in common. You know the area so what you can do solve for r from the equation for area of circle,
\[\sqrt{\frac{ A }{ \pi }}=r\]

Take that and plug into the circumference equation

\[C=2 \pi \sqrt{\frac{ A }{ \pi }}\]

With this equation you can find the circumference of a circle when given the area of a circle.

Answer 3

ok.

Answer 4

From the area of the circle, get the radius of the circle.

A = π * r²
81π = π * r²
r = ? @TylerMckinney16

Answer 5

hey sorry i was asleep lol.

Answer 6

@Directrix

Answer 7

@Directrix @nincompoop @Photon336

Answer 8

@rebeccaxhawaii

Answer 9

C=2*pi*r

as you can see you don't have the value of "r" right now..
so try finding that first..
you can do that by using the method Directrix told..
can you find the value of r now?

Answer 10

could u show me how.

Answer 11

like how i set it up

Answer 12

From the area of the circle, get the radius of the circle.

A = π * r²
81π = π * r²
r = ?

Answer 13

508.94

Answer 14

?

Answer 15

no. O.o
how did you got that.. can you show how u did it?

Answer 16

Wait sorry i did something wrong ok i did what u said and got .31.9

Answer 17

the pi would cancel out on both sides .. do you agree on that?

Answer 18

Yeah.

Answer 19

so you are left with
81 =r^2
right?

Answer 20

yeah

Answer 21

take square root of 81.. what do u get?

Answer 22

9 is the square root of 81 right.

Answer 23

yes

Answer 24

you should check where you went wrong in calculating ok?
so r=9

Answer 25

ok and the answer is r=9?

Answer 26

its not the answer.. you need r to find the circumference..
you know the formula for it?

Answer 27

no

Answer 28

C=2πr
with this formula you can find it..
now you have the value of r.. plug it in this equation..

Answer 29

2.39 ?

Answer 30

no.
can you show me how you are doing?

Answer 31

r = C/2π

bC = 11.9 metres so the radius is 11.9/2π

That is 1.9 m to the nearest tenth.

Answer 32

right?

Answer 33

no.. you have to find the find the value of C.

C = 2*pi*r
you have the value of r. plug it in.

C= 2 *pi* 9

Answer 34

56.52?
9*3.14*2=56.52

Answer 35

yes.. but read the question carefully.. it says leave ur answer in terms of pi.
so dont put the value of pi..
but u did it right anyway

Answer 36

So i just put pi instead the value?
9*pi*2=56.52?

Answer 37

C=2*pi*9
C=18*pi.

just leave it like this.

Answer 38

ok cool.