Question

the cylinder has a height of 10cm, and a radius of 3cm. What is it's surface area?

Answer 1

The equation for the surface area of a cylinder is A = 2 π r h+2 π r^2
A=2(3.14)(3)(10)+2(3.14)(3)^2
A=188.4+36.52
A=244.92

Answer 2

surface area is the area on top+area on bottom+area around

the areas on top are circles so 2pir^2 is the total area of tops and bottoms

the area arounnd is a rectangle that has been curled, its legnth is the height of the cylinder and the width is the circumfernce of the circle on top so area of that is h2pir
add them

2pir^2+h2pir
subsitute since h=10 and r=3
2pi(3)^2+10(2)pi(3)
2pi9+20pi3
18pi+60pi
78pi cm^2 is surface aea
if aprox pi=3.14 then
SA=244.92 cm^2



SA=78pi cm^2 or 244.92 cm^2