Posted by **mary** on Monday, April 18, 2011 at 12:37pm.

find the surface area of a right cylinder with a diameter of 4cm and a height of 6cm. Round to the nearest hundredth.

Book answer is 100.53cm^2 I came up with 150.79cm^2

my work:

2rr(4)6)=150.79cm^2 What did I do wrong??

- Geometry -
**MathMate**, Monday, April 18, 2011 at 1:34pm
The book answer is correct.

There are two things you need to watch for:

1. The diameter is 4 cm means the radius is 2 cm.

For the formula 2πrh, you have substituted 4 for the radius, which therefore gave twice the value it is supposed to have, namely 75.40 sq.cm.

2. The other 25.13 comes from the area of the two ends, each given by πr². (Note: r=2 cm).

## Answer this Question

## Related Questions

- math - Find the volume and surface area of a right cylinder with radius 7.5 cm ...
- Please Check My Math Answers. Thanks! - Can someone please be kind enough to ...
- Surface Area - [Given] Fiber Linear Density = 1 denier = 1 g/9000m Fiber Density...
- geometry - A right cylinder has the radius of 5 centimeters and height of 22 ...
- geometry - An observatory has the shape of a right circular cylinder topped by a...
- Math for Ms. Sue please! Last math questions! - For numbers 1–3, find the ...
- Math - Math Problem: Find the area of a circle that has a radius of 14 feet. ...
- algebra - Find the volume of a right circular cylinder whose base has an area of...
- Geometry - For the given dimensions, find the area of each figure. If necessary ...
- geometry - A right cylinder has a radius of 3 and a height of 12. What is its ...

More Related Questions