Problem of the day

Write a formula to find the perimeter of a regular octagon. Find the perimeter if one side is 12 cm.

Triangle Sum Rule

•How many degrees in a triangle?

180

•Diagonal – line segment that connects two non-adjacent vertices of a polygon

Example 1

•How many diagonals does a nonagon have?

Example 1

Example 1

Example 2

Example 3

Quick Check

•How many diagonals does a dodecagon have?