Shape and Space · JHS1 Mathematics

Lesson notes

Learning Objectives

Indicator: B7.3.1.2.1 - Construct a line segment perpendicular to another line segment.

By the end of the lesson, learners can:

State the meaning of perpendicular lines as lines that meet or intersect at a right angle (90 degrees).
Use a pair of compasses and a ruler to construct a perpendicular line at a given point on a line segment, following the correct sequence of steps.
Use a pair of compasses and a ruler to drop a perpendicular line from a given point outside a line segment, following the correct sequence of steps.
Identify the right angle formed where the constructed perpendicular meets the original line segment.
Apply the skill of constructing perpendicular lines to solve practical problems involving right angles.

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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: B7.3.1.2.1 - Construct a line segment perpendicular to another line segment.
Suggested placement: Term 2, Week 10 (Week 22 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. 51
Transcribed from the official NaCCA publication. Check this page against the source.

Exemplars (from the NaCCA curriculum)

E.g.1: Use a pair of compasses and a ruler to construct a copy of a given line segment. For instance, Line segment RS is a copy of PQ.

Wide black-and-white mathematical teaching visual is organised as a table with horizontal divisions, vertical... — A wide black-and-white mathematical teaching visual is organised as a table with horizontal divisions, vertical divisions, open white space around the main marks. The wide black-and-white table is arranged with horizontal divisions, vertical divisions, open white space around the main marks.

E.g.2: Use a pair of compasses and ruler to construct a perpendicular at a point on a line segment, and drop a perpendicular from a given point outside a line segment.
(i) A perpendicular at a point on a (ii) A perpendicular from a given point line segment: outside a line segment:

Wide colour mathematical teaching visual is organised as a table with horizontal divisions, vertical divisions,... — A wide colour mathematical teaching visual is organised as a table with horizontal divisions, vertical divisions, coloured regions. The wide colour table is arranged with horizontal divisions, vertical divisions, coloured regions.