Question

Find the circumference and area of a circle with a 12-cm diameter.

Answer 1

where do i even start

Answer 2

Do you know these formulas?
C=pi*d
A=pi*r^2

Answer 3

no

Answer 4

please explain

Answer 5

haha, that explains it then. C is circumference and A is area. d is diameter, which is 2r (or 2 times the radius) and r is radius. pi is\[\pi \]

Answer 6

So, you can plug 12 into d for C=pi*d. And you can divide 12 by 2 to find r, which you can plug into A=pi*r^2
Does it make sense?

Answer 7

area or circumference. which is the radius?

Answer 8

radius is r. hmm, try the first equation for circumference: C=pi*d and I can coach from there, if you want.

Answer 9

c=pi*12
that is how it would be set up right?

Answer 10

yeah. do you know if you're supposed to estimate pi as 3.14?

Answer 11

no

Answer 12

ok. then just leave the answer as 12*pi. How far can you get with the second equation?

Answer 13

a=pi*12

Answer 14

a=3.14*12= so area is 37.68

Answer 15

well, actually, \[a=\pi r^{2}\] so you would divide 12 by 2 to get r=6. Then square 6 to get 36, and multiply that by pi

Answer 16

so the frmula would look like a=3.14*6Squared

Answer 17

yeah. I'm not sure if you knew but "^" stands for "to the power of", btw.

Answer 18

oh ok now i knw

Answer 19

thank you so much for your help

Answer 20

no problem :)