find the surface area of a cylinder with a height of 25inches and a radius of 8in. Round to the nearest tenth?

Question

a. 1658.8in^2
b. 1457.7in^2
c. 1256.6in^2
d. 1053.1in^2

Answer 1

The answer is A. The area for the top and bottom is given by A=Pi*R^2. Multiply this by 2 for the top and bottom.

Then, find the circumfrerence by using the equation Pi*D.

Then multiply the circumfrerence by the hieght. This gives you the area of the sides.

Then, add the area of both top and bottom circles with the area of the sides, and this will give you the answer.

Answer 2

Easiest way to do this is to unroll the cylinder into a rectangle.
The circumference is 2 x pi x radius = 50.265 sq in, this would become the width of the rectangle. The height of the rectangle would be 25 in.

Area of side = h x w = 25 x 50.265 = 1256.64 sq in

But now we have the top and bottom, which are circles:

Area of top = area of bottom = pi x radius squared

Area of top = 64 x pi = 201.06 sq in

So the total surface area is side + top + bottom = 1256.64 + 201.06 + 201.06 = 1658.8 sq in.

Answer is a.

Answer 3

The bases are circles, so each base is pi*r^2.

The side of the cylinder is a bent rectangle, with the top side equal to the circumference of the circular base. So base * height = 2*pi*r*h.

Good luck!

Answer 4

SA = 2 * pi * R * H (for the outside)
SA = pi * r^2 (for the top)
SA = pi * r^2 (for the bottom)

use your calculator and learn all the formulas

Answer 5

circumference = 2 pi r
= 50.27

We have a rectangle now with sides of 50.27 and 25

Area = 50.27*25 = 1256.6 in^2 (c)