The Polygon Angle Sum Theorems

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)

• The measure of the largest interior angle

• The number of sides of the polygon

• Nothing

• The number of triangles that compose the polygon

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 sum of the interior angles of a nonagon.

• 1260

• 900

• 1620

• 180

Solve for x. 

(**HINT: Don't just assume the angles are symmetrical!)

• 100

• 120

• 125

• 130

What is the sum of the measures of the exterior angles of a decagon?

• 1440⁰

• 360⁰

• 144⁰

• 1800⁰

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

Solve for x. 

• 100

• 120

• 125

• 130

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