Question 174099
Could you give me the surface area of a cylinder when the radius is 6cm and the Length is 21cm.

You need a formula and it is

surface area = 2(πr^2) + 2(πr)(h), where r = radius, h = height 
and π = pi = 3.14

I guess by length you meant to type height.

Let SA = surface area of cynlinder for short.

SA = 2(3.14)(6)^2 + 2(3.14)(21)

SA = 226.08 + 131.88

SA = 357.96cm^2