Did I do this wrong?

Given a cylinder with a surface area of 60 units squared and a height of 7 units. Find the volume of a sphere that has the same size radius as the given cylinder. Show all work.

2πr^2+2πrh = 60 pi
2pi(r^2 + rh)=60pi
r^2+r•h=30
h =7
r^2+7•r=30
r(r+7) =30
if r = 3 then 3(3+7)=30 √
r=3

Question

Did I do this wrong?

Given a cylinder with a surface area of 60  units squared and a height of 7 units. Find the volume of a sphere that has the same size radius as the given cylinder. Show all work.

2πr^2+2πrh = 60 pi 
2pi(r^2 + rh)=60pi
r^2+r•h=30
h =7 
r^2+7•r=30
r(r+7) =30 
if r = 3 then 3(3+7)=30 √
r=3

anonymous · Answer

I think so.
I got the same answer: r=3
just put in formula for the volume of a sphere.

anonymous · Answer

then what do i do next?

i dont think im finished with the equation.

anonymous · Answer

You have to find the volume of the sphere that has that radius.

anonymous · Answer

though, I solve quadratic equation for r by using quadratic formula.
answer= the same

anonymous · Answer

V=4/3 pi*r
put r=3 in a formula

anonymous · Answer

So just plug it into the equation for the volume of a sphere.

anonymous · Answer

Thank You!

anonymous · Answer

is it 4/3πr^3
or just 4/3πr?

anonymous · Answer

I think u need find radius

anonymous · Answer

you already have radios: r=3 from the previous calculations

anonymous · Answer

It's $$V = \frac{4}{3}\pi r^3$$