Shape and Space · JHS1 Mathematics

Lesson notes

Learning Objectives

Indicator: B7.3.1.2.7 - Describe examples of perpendicular line segments, perpendicular bisectors and angle bisectors in the environment.

By the end of the lesson, learners can:

Identify real-life examples of perpendicular line segments in structures and artefacts around them and explain why the lines are perpendicular.
Locate and describe perpendicular bisectors in everyday objects, such as boxes, doors, and building features, stating what each bisector does to the line segment.
Recognise angle bisectors in artefacts and tools, such as folding chairs, scissors, or roof trusses, and describe how the bisector divides the angle.
Estimate the size of angles in environmental objects and classify whether a given angle is acute, right, obtuse, or reflex, drawing on skills from Term 2.
Communicate findings clearly in small groups, using precise geometric language such as “perpendicular”, “bisect”, and “midpoint” to describe objects in their surroundings.

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Curriculum details

Strand: Geometry and Measurement (Strand 3)
Sub-strand: Shape and Space (3.1)
Content standard: B7.3.1.2 - Demonstrate how to construct a perpendicular to a line from a given point, bisect a line, bisect angles, and construct angles of the following sizes: 30˚, 45˚, 60˚, 75˚
Indicator: B7.3.1.2.7 - Describe examples of perpendicular line segments, perpendicular bisectors and angle bisectors in the environment.
Suggested placement: Term 3, Week 1 (Week 25 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: Mathematics, Common Core Programme (JHS1-JHS3), 2023, p. 58
Transcribed from the official NaCCA publication. Check this page against the source.

Exemplars (from the NaCCA curriculum)

E.g.1: Identify angle bisectors and perpendicular bisectors in structures and artefacts such as buildings, water tanks, boxes, etc. in the environment
E.g.2 Estimate the measure of the size of angles in artefacts, tools, and structures.