Perimeter  a lesson with video and varied exercises
This third grade geometry lesson explains the concept of perimeter and has varied exercises for students. The included video explains some of the same ideas.
Perimeter means the
“walkaround measure,” or the distance you go if you walk all The word comes from the Greek word perimetros.
In it, peri means 'around' and metros 
^{
}To
find the perimeter of this rectangle, count the units as you go The units are marked with
little arrows in the
picture. The top side is So, what is the perimeter? _______ units 
Here it is trickier to count those little units. Be careful! How many units is the perimeter? _______ units 
1. Find the perimeter of these figures. Your answer will be so many units. P means perimeter.







2. Measure with a ruler to find the perimeter of these figures in centimeters.




To find the perimeter, simply How many units is the perimeter It is 8 + 9 + 10 units, or _______ units. 

Often you need to figure out some side lengths that are not given. What side lengths are not given? The perimeter is _______ cm. 

Don't forget the unit of measurement in
your answer. If the side lengths are in centimeters, the perimeter will be somany centimeters. If the side lengths are “plain numbers” without
any particular unit, then the 
4. Find the perimeter. Notice:
some side lengths are not given! Don't forget to use either “cm”
or “in.” or “units” in your answer.
P = units 
P = ________________ 
P = ________________ 
5. Find the perimeter....
a. ...of a square with 7in. sides
b. ...of a square with 13cm sides
This lesson is taken from Maria Miller's book Math Mammoth Early Geometry, and posted at www.HomeschoolMath.net with permission from the author. Copyright © Maria Miller.
Math Mammoth Early Geometry
A selfteaching worktext for 1st  3rd grade that covers basic shapes, right angle, symmetry, area, perimeter, and solids.
Download ($5.95). Also available as a printed copy.