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Cogito

Grade 7 Math · Chapter 7 · Lesson 4

Practice Worksheet

Telling Area from Circumference

Which question is being asked.

10 problems · about 18 minutes · 7.G.B.4

NameDate

Figure — use these to answer the problems

One circle, both measurements. Watch which one grows faster.
d = 8
  • Diameter8 cm
  • Circumference25.13 cm
  • Area50.27 cm²
  • Circumference ÷ diameter3.14
Radius4
Figure 1

Warm-Up Review

From earlier lessons. Loosen up before the new work.

3 problems

  1. From “Area of a Circle”

    Diameter 16. What is r² ?

    Answer

  2. From “Area of a Circle”

    Radius 4, π = 3.14. Area?

    Answer

  3. From “Measuring a Circle”

    Diameter 50, using π = 3.14. Circumference?

    Answer

Warm Up

Straightforward practice. Get the method working first.

3 problems

  1. Edging a round rug. 1 for circumference, 2 for area.

    Answer

  2. Ribbon around a cake. 1 for circumference, 2 for area.

    Answer

  3. Icing on top of a cake. 1 for circumference, 2 for area.

    Answer

Build It Up

The same ideas with more to keep track of.

2 problems

  1. An answer in square metres. 1 for circumference, 2 for area.

    Answer

  2. Radius 5. What is 2r?

    Answer

Stretch Yourself

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

2 problems

  1. The Fence

    Fencing a circular garden. Which is needed? Answer 1 for circumference, 2 for area.

    Answer

  2. The Turf

    Laying turf on that garden. Which is needed? Answer 1 for circumference, 2 for area.

    Answer