Perimeter of regular polygons
(A polygon is a shape with at least 3 straight, closed sides.)
If you need a reminder about perimeter, go back to Monday's lesson for the video & powerpoint.
We can calculate the perimeter of regular polygons even when the length of every side is not given e.g.
We know the perimeter must be 48m, because every side of a square is equal length!
What about rectangles?
The perimeter must be 16cm. Why? Because opposite sides of a rectangle are equal length.
Can you calculate the perimeter of this regular octagon?
That's right, it's 8 lots of 20cm, so 160cm! Because a regular octagon has 8 sides of equal length.
8X20cm = 160cm
Your task is to complete one of the attached: