Sample Question
Estimate the perimeter and area of the figure marked on the grid below. Each grid mark represents 5 miles.
Sample Response
Perimeter
To find the perimeter you can use a piece of string or follow the edge of the figure using marks on the side of a piece of paper. Remember the side of each square is 5 miles long. However you choose to measure the perimeter, you should come close to a measurement between 130 and 140 miles.
Area
Since the edge of each square is 5 miles, the area of one square would be 25 miles2.
First count the number of whole squares. Then you will have to combine the partial squares and estimate how many whole squares they would make. This is shown in the picture below where two partial squares are combined with two lines to make a whole square.
There are estimated to be 46 complete squares in this shape.
Remember that each square is 25 miles2. So you need to mulitply the number of squares by the area of each square.
A = (25)(46)
A = 1150 miles2