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

  3. 3.What is the name for the point exactly in the middle of a circle?

  4. 4.Tap the centre that is marked.

    Write the number of the part.

    123

  5. 5.Tap the radius.

    Write the number of the part.

    123

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

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

  7. 7.A circle has a radius of 6 cm. What is its diameter, in centimetres?

    • a) 6
    • b) 36
    • c) 12
    • d) 3

  8. 8.Put these circles in order by size, smallest first.

    • diameter 10
    • radius 4
    • radius 7
    • radius 2
    • diameter 6

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

  1. 1. radius
  2. 2. diameter
  3. 3. centre
  4. 4. 3 — The centre
  5. 5. 1 — The radius
  6. 6. radius 3 → 6; radius 5 → 10; radius 8 → 16; radius 11 → 22
  7. 7. c) 12
  8. 8. 1. radius 2 2. diameter 6 3. radius 4 4. diameter 10 5. radius 7