Two similar cylinders have heights 6 inches and 15 inches.

What is the ratio of their surface areas?
8 : 25

9 : 10

4 : 25

9 : 25

Question

Two similar cylinders have heights 6 inches and 15 inches. 

What is the ratio of their surface areas?
8 : 25

 9 : 10

 4 : 25

 9 : 25

anonymous · Answer

What is the formula for a cylinder?

anonymous · Answer

Erm, the formula for the Surface area of a cylinder?

anash · Answer

pi*r2*h?

anonymous · Answer

you know that r is the same, so you don't need to consider it, put the other values into an equation.

anonymous · Answer

Although use the actual formula $$Area = 2 \pi r(r+h)$$

anash · Answer

so 2*3.14(6+15)

anonymous · Answer

that's one, now do the other one and you will have the ratio.

anash · Answer

what other one?

anonymous · Answer

The formula's are
2*3.14(15)
2*3.14(6)
You forgot to remove the second radius

anash · Answer

so the first answer is 94.2 and the second one is 37.68