Unit 4 Part 2Regular Polygons

Polygons are a enclosed flat (on the same plane) shape.

Polygons

Triangle has 3 sides Quadrilateral has 4 sides Pentagon has 5 sides Hexagon has 6 sides Heptagon has 7 sides Octagon has 8 sides Nonagon has 9 sides Decagon has 10 sides Hendecagon has 11 sides Dodecagon has 12 sides

Names of Polygons

All angles are equiangular and all sides are equilateral. ( Meaning all the side and angles are the same size )

Regular Polygons

To find the total number of degrees inside any polygon use the formula below.

Polygons

Triangle has 3 sides , 180 degrees Quadrilateral has 4 sides , 360 degrees Pentagon has 5 sides , 540 degrees Hexagon has 6 sides , 720 degrees Heptagon has 7 sides , 900 degrees Octagon has 8 sides , 1080 degrees Nonagon has 9 sides , 1260 degrees Decagon has 10 sides , 1440 degrees Hendecagon has 11 sides , 1620 degrees Dodecagon has 12 sides , 1800 degrees

Total degrees of Polygons

Exterior angles of any polygon = 360°

A

E

D

C

B

To calculate a single exterior angle of a regular polygon use the formula below.

Exterior Angle of a Regular Polygon

The name of the polygon WATER is a _____________ If ∠W =(3x +1)°, ∠A=(2x+9)°, ∠T=(2x+10)°, ∠E=(x+128)°, and ∠T=(x+131)°, then determine the size of each angle.

Solution

Examples

A

R E

TW

What is the size of an exterior angle of a Dodecagon?

Example