# math

posted by
**Emily**
.

Okay. So i'm doing this project for my geometry class about different sports, soccer, baseball, basketball, bowling, golf, volleyball and pool. I have to find the surface area, volume, diameter, circumference, and radius of each of the balls. I got a circumference for each one and I know the formula for circumference is **diameter*pi**

How would I find the diameter if I only have the circumference?

And I think the formula for surface area, i need the one for a sphere. Is that **T=4pi r^2**? And then is the volume **V=4/3 pi r3**

thanks for the help :]

you have the right formulas.

If you have the circumference of the ball, then, if you consider a cross-section of the ball, you are looking at the circumference of a circle.

so, if for example the circumference is 65 cm, then

65 = 2pi*r

r=65/(2pi)

r= 10.3

once you have the radius, just plug it into the volume and surface area formulas, I am sure you know what to do.