New
New
Checking and securing understanding of constructing the perpendicular bisector of a line segment
I can use the properties of a rhombus to construct a perpendicular bisector of a line segment.
Lesson 1 of 13
New
New
- Year 11
Checking and securing understanding of constructing the perpendicular bisector of a line segment
I can use the properties of a rhombus to construct a perpendicular bisector of a line segment.
Lesson details
Key learning points
- A rhombus can be constructed from two congruent isosceles triangles
- The diagonals of a rhombus meet at right angles and bisect each other
- It is possible to construct the perpendicular bisector of a line segment without drawing the rhombus
- The line segment could be part of a shape
Keywords
Bisect - To bisect means to cut or divide an object into two equal parts.
Perpendicular - Two lines are perpendicular if they meet at right angles.
Rhombus - A rhombus is a parallelogram where all sides are the same length.
Common misconception
"My construction didn't accurately bisect the line segment"
Check that your compasses construct a full circle, and do not slip (and create a spiral-shape). Tighten the screw on your compasses, if possible. Then, if only using construction arcs that look confusing, you can construct full circles to help.
If your pupils need further support on this, you can find more lessons in the year 8 constructions unit.
Teacher tip
Equipment
Pair of compasses, ruler.
Licence
This content is © Oak National Academy Limited (2026), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.A is a parallelogram where all sides are the same length and the angles are not equal to 90°.
A is a parallelogram where all sides are the same length and the angles are not equal to 90°.
Q2.Sofia takes this item from her geometry set. What is the name of this item?
Sofia takes this item from her geometry set. What is the name of this item?
protractor
ruler
set square
Q3.Jacob takes this item from his geometry set. What is the name of this item?
Jacob takes this item from his geometry set. What is the name of this item?
pair of compasses
ruler
set square
Q4.Triangle ABC has 2 equal sides and 2 equal angles. What type of triangle is ABC?
Triangle ABC has 2 equal sides and 2 equal angles. What type of triangle is ABC?
Q5.A is a quadrilateral with two pairs of parallel and equal sides.
A is a quadrilateral with two pairs of parallel and equal sides.
Q6.Part of a circle's circumference is called...
Part of a circle's circumference is called...
a chord
a diameter
a sector
a segment
Assessment exit quiz
6 Questions
Q1.To means to cut or divide an object into two equal parts.
To means to cut or divide an object into two equal parts.
Q2.Select the properties of a rhombus.
Select the properties of a rhombus.
All the angles are of equal size
4 lines of symmetry
Q3.Two triangles are put together to form a quadrilateral. Which quadrilateral is a rhombus?
Two triangles are put together to form a quadrilateral. Which quadrilateral is a rhombus?
Q4.Aisha correctly draws three of the four arcs needed to construct the perpendicular bisector of LM. Point A is 5 cm away from point L. Point B is cm away from point M.
Aisha correctly draws three of the four arcs needed to construct the perpendicular bisector of LM. Point A is 5 cm away from point L. Point B is cm away from point M.
Q5.Jacob correctly draws three of the four arcs needed to construct the perpendicular bisector of AB. Which of these statements is correct?
Jacob correctly draws three of the four arcs needed to construct the perpendicular bisector of AB. Which of these statements is correct?
Point C is closer to A than B.
Point C is closer to B than A.
It is impossible to tell if C is closer to A or B.
Q6.Which of these diagrams show an accurate construction of a perpendicular bisector of the line segment AB?
Which of these diagrams show an accurate construction of a perpendicular bisector of the line segment AB?
