Skip to lesson

Choose “Save as PDF” in the print dialog to keep a copy.

Cogito

Grade 7 Math · Chapter 7 · Lesson 1

Practice Worksheet

Measuring a Circle

Where π actually comes from.

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

NameDate

Figure — use these to answer the problems

Change the radius. The ratio at the bottom stays put.
d = 6
  • Diameter6 cm
  • Circumference18.85 cm
  • Circumference ÷ diameter3.14
Radius3
Figure 1

Warm-Up Review

From earlier lessons. Loosen up before the new work.

2 problems

  1. From “Solving Inequalities”

    4x > 20. Smallest whole number x?

    Answer

  2. From “Solving p(x + q) = r”

    6(x + 2) = 42. What is x?

    Answer

Warm Up

Straightforward practice. Get the method working first.

4 problems

  1. Diameter 50, using π = 3.14. Circumference?

    Answer

  2. What is π?

    • Circumference divided by diameter.
    • Just a number someone chose.

  3. Diameter 10, using π = 3.14. Circumference?

    Answer

  4. Radius 4. What is the diameter?

    Answer

Build It Up

The same ideas with more to keep track of.

2 problems

  1. Diameter 100, using π = 3.14. Circumference?

    Answer

  2. Circumference divided by diameter is about what?

    Answer

Stretch Yourself

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

2 problems

  1. The Wheel

    A wheel has diameter 20 cm. What is its circumference, using 3.14 for π?

    Answercm

  2. The Radius

    A circle has radius 5 cm. What is its diameter?

    Answercm