Measurement - Area #1

Review of Finding the Perimeter of a shape

What is area and how is it measured? Why are square units used?

We know that a postage stamp is the smallest item on the list so the most reasonable guess is that its area would be 4 square centimetres. We tried to visualize what that would look like then made it using centimetre cubes. The length x width formula clearly worked. We counted 4 cubes, therefore the space it takes up (area)  is really 4 square centimeters.

Next, we wanted to visualize what the sheet of paper with 900 square centimetres would look like. First we had to think of the formula for area. What two numbers when multiplied would result in 900?

Thinking of possible dimensions for the length and width of the paper we came up with the following:

We then eliminated the dimensions that did not seem reasonable for a sheet of paper (100 x 9 , 300 x 3 and 225 x 4). Students had to measure the remaining dimensions on their desks in order to figure out which one would resemble a standard sheet of paper.

Too square

Too elongated (long and narrow)

Seems like a reasonable size for a sheet of paper

The take away from this task was a BIG learning discovery:

All the shapes have the exact same area of 900 square centimetres BUT the dimensions were different.

Conclusion: It's possible for shapes to have the same area but different perimeters.