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3rd grade · Math · Unit 9 of 14

Area & Perimeter

Around and inside shapes

What your child practices

Finding the perimeter (distance around) of rectangles and triangles, finding a missing side, and measuring area in square centimeters and square meters.

California Content Standards learning standard: 3.MD.5; 3.MD.6; 3.MD.7; 3.MD.8 · measuring area with unit squares, relating area to multiplication, and solving perimeter problems

How we explain it

Children can open this short lesson before they practice.

  1. Perimeter is the distance around a shape. Add all sides.
  2. Area is the space inside. Count the square units.
  3. Perimeter uses cm. Area uses square cm.

Example: A rectangle is 5 cm long and 3 cm wide. What is its perimeter? Add all four sides: 5 + 3 + 5 + 3. That is 16 cm. Answer: 16 cm

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    A rectangle is 8 cm long and 3 cm wide. What is its area, in square centimeters?

    • 24
    • 23
    • 20

  2. Question 2

    Which unit is best for the area of a classroom floor?

    • meters
    • square centimeters
    • square meters

  3. Question 3

    A rectangle has a perimeter of 28 cm. It is 8 cm long. How wide is it, in centimeters?

    • 6
    • 3
    • 1

  4. Question 4

    A rectangle is 4 cm long and 2 cm wide. What is its perimeter in centimeters?

    • 14
    • 16
    • 12

  5. Question 5

    A rectangle is 5 cm long and 2 cm wide. What is its area, in square centimeters?

    • 8
    • 4
    • 10

  6. Question 6

    Which rectangle has the same area as a 2 by 8 rectangle?

    • 4 by 5
    • 4 by 4
    • 3 by 8

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