PLEASE HELP I'M DESPERATE. SURFACE AREA of a cylinder.

Question

Okay so I have this question on surface area of a cylinder. Simple right?

Well the formula is SA = 2πr2 + 2πrh right?

So i plug in my numbers. The question is, Cylinder A has a radius of 2 inches and a height of 2 inches. Cylinder B has a radius of 2 inches and a height of 4 inches. Calculate the surface area for both cylinders.

So i plug in my numbers SA=2 x 3.14 x radius squared which for cylinder A is 2 squared making it 4 right? So, SA= 2 x 3.14 x 4? When i put this in and solve for it I get 25.12, now you add 2 x 3.14 x 2 x 2 right? Or do you use the squared version, making it 4? Either way EVERY TIME i solve for it i get something WAY HIGHER than the available answers, it says the answer is A: 16π in2; B: 24π in2.!!?!?!!?!??! IM SO LOST i'm begging anyone to show me how this is the answer :(
also i'm very tired

Answer 1

Note that your answer choices did not convert pi to 3.14.. It just left it as π

 

SA = 2πr² + 2πrh

 

Cylinder A has a radius of 2 inches and a height of 2 inches:

 

SA_A = 2π(2)² + 2π(2)(2) = 8π + 8π = 16π in²

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Cylinder B has a radius of 2 inches and a height of 4 inches

 

SA_B = 2π(2)² + 2π(2)(4) = 8π + 16π= 24π in²

 

If you need total surface area as the sum of both cylinders it would be 40π in²