Question

What is the surface area of a cylinder with the hight of 7 and the diameter of 9​

Answer 1

Explanation:

for this, you need to remember a formula for the curved bit of the cylinder. The top and the bottom circles are easy since you only need to find their areas which are πr^2 therefore to find the radius you half 9. So 4.5^2 x π =63.62 then times two as there are two parts.

63.62 x 2 =127.24

For the curved, long bit use formula of 2πhr.

2 x π x 7 x 4.5 =63π =197.92