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Grade 7 · Math · Unit 11 of 15

Constructions

Perpendicular lines, parallel lines and bisectors

What your child practises

Children practise the ideas behind geometric constructions: perpendicular and parallel lines, perpendicular bisectors and angle bisectors made with a compass and straightedge.

Manitoba Curriculum learning outcome: 7.SS.3 · geometric constructions: perpendicular and parallel lines, perpendicular bisectors and angle bisectors

How we explain it

Children can open this short lesson before they practise.

  1. Perpendicular lines meet at 90°. Parallel lines never meet.
  2. A perpendicular bisector cuts a line segment in half at 90°.
  3. An angle bisector cuts an angle into two equal angles.

Example: An angle of 80° is bisected. How big is each new angle? Bisect means cut in half. 80 ÷ 2 = 40. Answer: 40°

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    Each of the two parts of a bisected angle measures 25°. The original angle measures…

    • 50°
    • 100°
    • 25°
    • 12.5°

  2. Question 2

    If a 70° angle is bisected, each part measures…

    • 70°
    • 35°
    • 140°
    • 20°

  3. Question 3

    To bisect angle ABC, you first draw an arc from B that crosses…

    • both arms of the angle
    • neither arm
    • the page edge
    • only one arm

  4. Question 4

    Which pair of lines is parallel?

    • two sides that meet at a corner
    • the opposite sides of a rectangle
    • a vertical and a horizontal line
    • the hands of a clock at 3:00

  5. Question 5

    If a 90° angle is bisected, each part measures…

    • 180°
    • 30°
    • 45°
    • 90°

  6. Question 6

    The diagonals of a rectangle that is not a square…

    • are perpendicular
    • bisect each other but are not perpendicular
    • do not cross
    • are parallel

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