Polygon Sum Theory

The sum of the interior angles of a polygon is __________________ where n is the number of sides.

• (n - 2)180

• (n - 1)180

• 360

• (n - 3)(180)

Find the sum of the interior angles of a nonagon.

• 1260

• 900

• 1620

• 180

Find the measure of ONE exterior angle of a regular decagon.

• 36

• 10

• 18

• 40

Find the measure of ONE interior angle of a regular dodecagon.

• 150

• 120

• 1800

• 20

The sum of the exterior angles of a polygon is __________________ where n is the number of sides.

• 360

• n

• (n - 2)180

• (n - 1)180

Find the measure of angle E.

• 9

• 97°

• 48°

• 79°

Solve for x. 

• 100

• 120

• 125

• 130

Find the value of X.

• 60

• 120

• 85

• 55

A polygon's interior angles add up to 2700.  How many sides does the polygon have?

• 17

• 15

• 19

• 11

Find the measure of one interior angle in regular 25-gon. Round your answer to the nearest tenth if necessary.

• 164.3⁰

• 167.1⁰

• 165.6⁰

• 166.7⁰