Essential Questions for Perimeter
1. Explain what perimeter is, and why it is important.
2. What is the difference between a regular polygon, and an irregular polygon?
3. How do you find the perimeter of a regular polygon? Of an irregular polygon?
4. Explain how knowing to match the opposite sides of a rectangle to show they are of
equal length, helps find perimeter.
5. How do you find the perimeter of a polygon when the side measurements are not
given?
Regular Polygon
Irregular
Polygon
Perimeter ~
Rectangle
Rectangle
8 feet
X
Count units
Equal lengths
Perimeter = 24 feet
Side
+
A polygon with all sides
and all angles equal
Formula:
(X) x (side)
a
Irregular Polygon ~
A polygon whose sides
and angles are not all
congruent.
=
Side
Perimeter ~
Rectangle: a two-dimensional,
The sum of the distance of all the
lengths of the sides of an object.
four-sided shape with two pairs of
equal-length, parallel sides and four
right angles
8 feet
a
b
Match the opposite sides of a
rectangle to show they are of
equal length.
a
X
b
Count units
Perimeter = 24 feet
Perimeter = 8 + 8 + (x) + (x) = 24 feet
8 + 8 + 4 + 4 + = 24 feet
+
+
Side
Side
Regular Polygon ~