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Cogito

Grade 3 Math · Chapter 4 · Lesson 8

Practice Worksheet

Area of Joined Shapes

Split an odd shape into rectangles.

10 problems · about 13 minutes · 3.MD.C.7

NameDate

Figure — use these to answer the problems

Cut the shape into two rectangles and add their areas.

4 × 7 = 28

4 × 7 = (4 × 3) + (4 × 4) = 12 + 16 = 28

Height4
Width7
Cut after this column3
Figure 1

Warm-Up Review

From earlier lessons. Loosen up before the new work.

3 problems

  1. From “Same Area, Different Shape”

    A 2 by 9 rectangle. What is its area?

    Answer

  2. From “Telling Area and Perimeter Apart”

    A rectangle 9 by 4. What is its area?

    Answer

  3. From “Perimeter”

    A rectangle 9 by 5. What is its perimeter?

    Answer

Warm Up

Straightforward practice. Get the method working first.

3 problems

  1. A 6 by 3 part and a 4 by 2 part. Total area?

    Answer

  2. What do you do with an odd-shaped floor?

    • Split it into rectangles.
    • Estimate the area by eye.

  3. A 4 by 4 part and a 2 by 3 part. Total area?

    Answer

Build It Up

The same ideas with more to keep track of.

1 problem

  1. A 5 by 5 part and a 2 by 2 part. Total area?

    Answer

Stretch Yourself

Mixed problems. Work out what kind of question it is before you start.

3 problems

  1. A 7 by 2 part and a 3 by 4 part. Total area?

    Answer

  2. The L-Shaped Room

    A room splits into a 5 by 3 part and a 2 by 4 part. What is the total area?

    Answersquare units

  3. The Patio

    A patio splits into a 6 by 4 part and a 3 by 3 part. What is the total area?

    Answersquare units