Lesson Notes By Weeks and Term v4 - JHS 1
Shape and Space
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Shape and Space
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Mathematics
Class: JHS 1
Term: 2nd Term
Week: 12
Grade code: B7.3.1.2.1
Strand code: 3
Sub-strand code: 1
Content standard code: B7.3.1.2
Indicator code: B7.3.1.2.1
Theme: GEOMETRY AND MEASUREMENT
Subtheme: Shape and Space
This page supports the lesson note with a companion video and a short classroom-ready summary.
For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.
This lesson introduces learners to the fundamental geometric skill of constructing perpendicular lines. In Ghana, we see perpendicular lines everywhere: in the corners of our classrooms, the way walls meet the floor in our homes, the design of the Black Star on our flag, and in the layout of farm plots. Understanding how to construct them accurately using only a compass and a ruler is a foundational skill for many technical and artistic fields like architecture, carpentry, and engineering. This lesson moves beyond simply drawing a right angle with a protractor to the precise method of geometric construction.
A. Core Vocabulary Line: A straight path that extends forever in both directions. We represent it with arrows at both ends. Line Segment: A part of a line with two definite endpoints. Perpendicular Lines: Two lines that intersect (meet or cross) to form a right angle. Right Angle: An angle that measures exactly 90 degrees (90°). It looks like the corner of a book or a window frame. The symbol for perpendicular is ⊥. So, if line AB is perpendicular to line CD, we write AB ⊥ CD. Construction: In geometry, this means to draw shapes, angles, or lines accurately using only a compass, a straightedge (ruler), and a pencil. We do not use a protractor to measure the angles during construction, but we can use it to check our work afterwards.
B. Required Tools A Pencil (sharpened) A Ruler (to be used as a straightedge) A Pair of Compasses
C. Construction Methods
There are two main scenarios we will learn today. Case 1: Constructing a perpendicular from a point ON the line.