Question

Find the surface area of the cylinder in terms of x.

Answer 1

Surface area in units of PI = 2 x r x h +2 x r^2

first picture:

r = 7, h = 18

2 x 7 x 18 + 2 x 7^2

252 + 98

350 PI cm^2

2nd picture:  

2 x 9 x 20  +2 x 9^2

360 + 162

522 PI in^2

Answer 2

Surface area = 2πr² + 2πrh  

Surface are = 2π (7)² + 2π(7)(18) = 98π + 252π = 350π cm²


Surface area = 2πr² + 2πrh  

Surface are = 2π (9)² + 2π(9)(20) = 162π + 360π = 522π cm²