How it works
Area is length times width. The way round, the perimeter, is two lengths and two widths.
If you know the area and one side, divide to find the other side.
If you know the perimeter and one side, take two of that side away and halve the rest.
Worked examples
The way round
- The card is 5 centimeters long and 4 centimeters wide. What is its perimeter?
- Add two lengths and two widths.
- 5 + 4 + 5 + 4 = 18.
- So the answer is 18.
Find a missing side from area
- The area is 480 square meters. One side is 80 meters. Find the other.
- Area ÷ the known side.
- 480 ÷ 80 = 6.
- So the answer is 6.
Find a missing side from perimeter
- The perimeter is 174 feet. One side is 33 feet. Find the other.
- Half of 174 is 87. That is one length plus one width.
- 87 − 33 = 54.
- So the answer is 54.
A taste of the worksheet
These are the first problems of set A. The printable sheet has many more, with an answer key.
- The patio is 5 meters long and 3 meters wide. What is its area__