Download Perimeter of Regular Polygons

Measurement # 2a
Perimeter of Regular Polygons
Definitions:
Regular Polygons: a shape that has all its angles and sides equal.
Rectangle: a shape that has opposite sides and all angles equal.
Rules for Finding the Perimeter of Regular Polygons
1. Use the equation P = n x s
P = perimeter, n = number of sides,
s = length of one side
2. If necessary, convert all sides to the same units.
3. Substitute the numbers into the equation.
4. Solve for the equation.
5. Express your answer with units.
6. The units for perimeter are to the power of 1.
Example: mm, cm, m, km.
Examples:
1.
P=nxs
P = 3 x 4m
P = 12m
4m
2.
5m
P=nxs
P=8x5m
P = 40 m
Rules for Finding the Length of one Side of a Regular Polygon when Given the
Perimeter.
1. Use the equation S = P
n
S = the unknown side, P = perimeter,
n = the number of sides
2. If necessary, convert all sides to the same units.
3. Substitute the numbers into the equation.
4. Solve for the equation.
5. Express your answer with units.
6. The units for the sides are to the power of 1.
Example: mm, cm, m, km.
Example:
1.
P = 20 m
s=P
n
s = 20 m
4
s=5m
S
Rules for Finding the Perimeter of a Rectangle.
1. Use either of the following two equations:
a) P = 2l + 2w
b) P = 2(l + w)
P = perimeter, l = length, w = width
2. If necessary, convert all sides to the same units.
3. Substitute the numbers into the equation.
4. Solve for the equation.
5. Express your answer with units.
6. The units for perimeter are to the power of 1.
Example: mm, cm, m, km.
Example:
1.
2 cm
4 cm
P = 2l + 2w
P = 2 x 4 cm + 2 x 2 cm
P = 12 cm
P = 2 x (l + w)
P = 2 x (4 cm + 2 cm)
P = 12 cm