## Monday, July 9, 2012

### Practice for regular polygon angles and pictures of regular tilings

Here is a link to practice problems from 2011 dealing with the angles of regular polygons.

Here are pictures of some mix and match tilings of the planes, which will be on the Tuesday homework.

Here are more regular polygon problems.

The formula for total degrees of the angles on an n-gon is 180(n-2)° or [180n-360]°.

The formula for the measure of a regular angle is [180-360/n]°.

a) What is the sum of all the angles of a 20-gon?

b) What is the regular angle measure of a 20-gon?

c) What is the sum of all the angles of a 30-gon?

d) What is the regular angle measure of a 30-gon?

#### 1 comment:

Prof. Hubbard said...

a) What is the sum of all the angles of a 20-gon?

(20-2)*180 = 3240°.

b) What is the regular angle measure of a 20-gon?

[180 - 360/20]° = [180 - 18]° = 162°

c) What is the sum of all the angles of a 30-gon?

(30-2)*180 = 5040°.

d) What is the regular angle measure of a 30-gon?

[180 - 360/30]° = [180 - 12]° = 168°