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Class 4 Maths — Circles: centre, radius and diameter

Name the centre, radius and diameter of a circle, and use the fact that the diameter is twice the radius.

Name: ________________________

  1. 1.What is the name for a straight line drawn from the middle of a circle out to its edge?

  2. 2.A circle has a diameter of 20 cm. What is its radius, in centimetres?

    • a) 20
    • b) 10
    • c) 5
    • d) 40

  3. 3.What is the name for a straight line that crosses a circle from edge to edge, passing through the middle?

  4. 4.Tap the radius.

    Write the number of the part.

    123

  5. 5.A circle has a diameter of 14 cm. What is its radius, in centimetres?

    • a) 28
    • b) 4
    • c) 7
    • d) 14

  6. 6.The diameter of a circle is always...

    • a) three times the radius
    • b) twice the radius
    • c) half the radius
    • d) the same as the radius

  7. 7.Match each circle's radius to the diameter of the same circle.

    • radius 3
    • radius 5
    • radius 8
    • radius 11
    • 6
    • 22
    • 16
    • 10

  8. 8.Tap the centre that is marked.

    Write the number of the part.

    123

Answer key — Class 4 Maths — Circles: centre, radius and diameter

  1. 1. radius
  2. 2. b) 10
  3. 3. diameter
  4. 4. 1 — The radius
  5. 5. c) 7
  6. 6. b) twice the radius
  7. 7. radius 3 → 6; radius 5 → 10; radius 8 → 16; radius 11 → 22
  8. 8. 3 — The centre