Estimate the perimeter and area of irregular figures. Perimeter. Step 1: Estimate
the perimeter by counting the units along each straight line in the figure.
Name
Reteach 16.5
Date
Perimeter and Area of Irregular Figures Estimate the perimeter and area of irregular figures.
Perimeter
Area
Step 1: Estimate the perimeter by counting the units along each straight line in the figure. Long straight side ⫽ 4 units Short straight side ⫽ 2 units
Step 2: Estimate the lengths of the curved sides. Long curved side ⬇ 4 units Short curved side ⬇ 1 unit
Step 3: Add the lengths of the sides.
Step 1: Estimate the area by counting the whole squares inside the shape. 4 whole squares
Step 2: Try to piece together partial squares to make whole squares. Count 1 each partial square as ᎏᎏ. 2 In the example, the partial squares 1 make about 2ᎏᎏ whole squares. 2
Step 3: Add the whole and partial squares.
4 ⫹ 2 ⫹ 4 ⫹ 1 ⫽ 11
1 1 4 ⫹ 2ᎏᎏ ⫽ 6ᎏᎏ 2 2 1 The area is about 6ᎏᎏ square units. 2
The perimeter is about 11 units.
Estimate the perimeter and area of each figure. Each square is 1 cm 2. 1.
2.
3.
Find the perimeter and area of each figure. All intersecting sides meet at right angles. 11 m
