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  • 3rd Grade
  • Math
  • About 10 minutes
  • See it all: a chart to keep

Area and Perimeter Strategies

Use what you know about area and perimeter to solve harder problems.

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Area and Perimeter StrategiesName:Date:Use what you know about area and perimeter to solve harder problems.Break apart to find areaABSplit the shape into two rectangles.A: 4 × 2 = 8 square unitsB: 2 × 3 = 6 square unitsArea = 8 + 6 = 14 square unitsFind a missing sideThe area is 20 square cm.5 cm? cmThinkmultiplication.5 × ? = 20The missing side is 4 cm.The perimeter is 20 cm.6 cm? cmOpposite sidesmatch.6 + 6 = 12, 20 − 12 = 8, 8 ÷ 2 = 4The missing side is 4 cm.Same area, different perimeter6 × 2: area 12perimeter 164 × 3: area 12perimeter 14Both have 12 squares inside,but the edges are different.Long, thin rectangles havebigger perimeters.k5printables.com · Sheet #85024601 · Aligned with Common Core 3.MD.C.7

How to do it

  1. Break an L shape into two rectangles to find its area.
  2. Use multiplication or the perimeter to find a missing side.
  3. Compare rectangles that have the same area.

Teaching tip

Use this chart before Break Apart to Find Area, Missing Side Length and Same Area, Different Perimeter. This sheet is aligned with Common Core 3.MD.C.7.

Area and Perimeter Strategies chart for 3rd grade, free printable
Printable preview

About this chart

Breaking shapes apart for area, finding a missing side from the area or perimeter, and same area with different perimeters.

What kids practice

Area is the amount of space inside a flat shape, measured in square units. Perimeter is the distance all the way around a shape, measured in units of length. Third graders find area by counting squares and then by multiplying length × width. They find perimeter by adding the side lengths, and learn that two shapes can have the same area but different perimeters.

Watch for

  • Mixing up area and perimeter. Area is inside; perimeter is around.
  • Adding only the two labeled sides of a rectangle instead of all four.
  • Writing area in plain units instead of square units.

It's free to print, as many copies as you need. See the full area and perimeter guide for 3rd grade.

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