Download Math 10 Geometry Unit Lesson 3

Math 10
Geometry Unit
Lesson 3
6.2 (1) Properties of a
Regular Polygon
What is a polygon???

A 2-dimensional closed figure with 3 or more
sides.
Regular Polygon –

all sides and angles are equal
Line Symmetry

Location where a shape can be folded in
equal halves.
Rotational Symmetry

A property where an object can be rotated
around its center and match the original
shape at least once before a full rotation.
Ex. Equilateral triangle.
To calculate angle measures of regular
polygons…

Divide 360 by the number of “lines of symmetry”
(number of sides) of a regular polygon to get the
angle located at the center of the shape.
ex: 360  6 = 60

Subtract this angle from 180 to get the interior
angles of the regular polygon.
To get the exterior angles you need to subtract this
from 180.
What do you notice???


Classwork


Properties of regular polygons sheet
Answer question 2 pg. 266