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Grade 4 Math — 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 — center to edge
  2. 2. Diameter — right across, through the center
  3. 3. Chord — edge to edge, missing the center

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

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

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

  2. 2.Sort each name by whether it describes a part of a circle or a part of an angle.

    Groups: Part of a circle · Part of an angle

    • Arm
    • Radius
    • Vertex
    • Center
    • Chord
    • Diameter

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

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

    • Octagon
    • Hexagon
    • Quadrilateral
    • Triangle
    • Pentagon

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

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

  6. 6.A line has no ends, a ray has one end, and a line segment has two. Which of the three has a length you could measure with a ruler?

    • a) A ray
    • b) All three of them
    • c) A line
    • d) A line segment

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

    Write the number of the part.

    123

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

Answer key — Grade 4 Math — Basic geometrical ideas

  1. 1. c) 14
  2. 2. Radius → Part of a circle; Diameter → Part of a circle; Chord → Part of a circle; Center → Part of a circle; Vertex → Part of an angle; Arm → Part of an angle
  3. 3. 6
  4. 4. 1. Triangle 2. Quadrilateral 3. Pentagon 4. Hexagon 5. Octagon
  5. 5. Triangle → 3; Quadrilateral → 4; Pentagon → 5; Hexagon → 6; Octagon → 8
  6. 6. d) A line segment
  7. 7. 2 — the line right across through the center
  8. 8. 2