← Back to the activity

Year 6 Maths — Basic geometrical ideas

Tell points, lines, rays and line segments apart, name the parts of an angle and a circle, and count the sides and diagonals of a polygon.

Name: ________________________

Before you start

Three lines are drawn on this circle. Take them in turn and find out what each one is called, looking at where each one starts and where it ends.

123
  1. 1. Radius — centre to edge
  2. 2. Diameter — right across, through the centre
  3. 3. Chord — edge to edge, missing the centre

Every diameter is also a chord — it is simply the longest one, and the only kind that passes through the centre.

  1. 1.Put these shapes in order by how many sides they have, fewest first.

    • Octagon
    • Pentagon
    • Triangle
    • Quadrilateral
    • Hexagon

  2. 2.Match each shape to the number of sides it has.

    • Triangle
    • Quadrilateral
    • Pentagon
    • Hexagon
    • Octagon
    • 6
    • 3
    • 4
    • 5
    • 8

  3. 3.Three straight lines have been drawn on this circle. Tap the diameter.

    Write the number of the part.

    123

  4. 4.An angle is made where two rays meet at a point. How many arms does one angle have?

  5. 5.Three points are marked, and no two of them are in the same place. How many different line segments can be drawn joining pairs of them?

  6. 6.How many line segments make up the sides of a hexagon?

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

    • a) 21
    • b) 3.5
    • c) 7
    • d) 14

  8. 8.How many diagonals can be drawn inside a quadrilateral?

Answer key — Year 6 Maths — Basic geometrical ideas

  1. 1. 1. Triangle 2. Quadrilateral 3. Pentagon 4. Hexagon 5. Octagon
  2. 2. Triangle → 3; Quadrilateral → 4; Pentagon → 5; Hexagon → 6; Octagon → 8
  3. 3. 2 — the line right across through the centre
  4. 4. 2
  5. 5. 3
  6. 6. 6
  7. 7. d) 14
  8. 8. 2