Polygons SUBTITLE Polygon Names What is a polygon

Polygons SUBTITLE

Polygon Names • What is a polygon? • What is a regular polygon? • What does it mean to be con. CAVE? • What does it mean to be con. VEX?

Can you list the names of the following polygons? Number of Sides Polygon Name Number of Sides 3 8 4 9 5 10 6 11 7 12 Polygon Name

Polygon Practice • Name the polygon, whether it is regular, whether it is concave or convex?

Polygon Angles How many triangles are in the polygon? How many degrees are in a triangle? How many degrees are the interior angles?

Polygon Angles Continued How many triangles are in the polygon? How many degrees are in a triangle? How many degrees are the interior angles?

Equations • Can we come up with an equation that gives the sum of the interior angles of a n-gon based on the number of sides? • Remember every equation must have a variable and an equal sign.

Exterior angles What is the measure of each interior angle? What is the measure of each exterior angle? What is the sum of the exterior angle?

Exterior Angles Continued What is the measure of each interior angle? What is the measure of each exterior angle? What is the sum of the exterior angle?

Exterior Angles Continued What is the measure of each interior angle? What is the measure of each exterior angle? What is the sum of the exterior angle? What is the equation for the sum of the exterior angles?

WARNING!!! These equations only work when the polygons are REGULAR

Practice • Assuming all shapes are regular polygons find the sum of the interior angles. Find the sum of the exterior angles. Find the measure of one interior angle and one exterior angle.

Practice • Do not assume they are regular pentagons. If they are regular find the sum of the interior and exterior angles. • Heptagon concave octagon regular decagon • Regular 18 -gon regular convex 50 -gon regular 94 -gon

More practice • The sum of the interior angles of a shape is 2700 assuming it is a regular polygon how many sides does it have? • Assuming a polygon is a regular polygon and it has an interior angle measure of 175 degrees how many sides does it have? Assuming a polygon is a regular polygon if an exterior angle is 10 degrees how many sides does the polygon have?