The formula S= 2 pi rh+ 2 pi r^2 gives the surface area S of a cylinder with height h and radius r. Solve the formula for h. Find h if r=5 cm and S=400 cm square.

Question

The formula S= 2 pi rh+ 2 pi r^2 gives the surface area S of a cylinder with height h and radius r.  Solve the formula for h.  Find h if r=5 cm and S=400 cm square.

aum · Answer

$S= 2 \pi rh+ 2 \pi r^2$
To solve for h, isolate h
Subtract $2\pi r^2$ from both sides:
$S - 2\pi r^2 = 2\pi rh$
Divide both sides by $2\pi r$
$\Large \frac{S - 2\pi r^2}{2\pi r} = h$

anonymous · Answer

Here you go!

anonymous · Answer

thanks so much guys :D
ur a great help!!

aum · Answer

Before plugging in the numbers they are asking you to solve for h first.
So do the steps in my first reply.  Then follow the image posted by phuongduongm.

anonymous · Answer

ohhhh okok i get it now. 
you guys are so helpful thanks so much :)