Class: Junior Secondary School 2 (JSS2, JSS 2)
Term: 1st Term
Week: 10
Age: 13 years
Duration: 45 minutes
Subject: Basic Science And Technology
Curriculum Theme: Basic Technology
Previous Lesson: Construction of Triangles, Circumscribing, Inscribing and Escribing Circles
Topic: Circle
Subject Matter: Definition, Types and Parts of a Circle, Construction of Tangents and Normals to a Given Circle and Two Equal and Unequal Circles

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:
(a) Define a circle and identify its parts.
(b) Distinguish between different types of circles.
(c) Explain the concept of tangent and normal to a circle.
Affective Domain:
(a) Appreciate the importance of geometric construction in daily life.
(b) Develop a positive attitude toward accuracy and neatness in drawing.
Psychomotor Domain:
(a) Construct tangents and normals to a given circle using mathematical instruments.
(b) Draw tangents and normals to two equal and unequal circles.
Social Domain:
(a) Work collaboratively in groups to practice geometric constructions.

Reference Materials

The following resources was used in planning this lesson:

9 Years Basic Education Curriculum
Lagos State Unified Scheme of Work for Junior Secondary Schools
Math is Fun – “Circle Geometry” (https://www.mathsisfun.com/geometry/circle.html)
Relevant Textbooks

Instructional Materials

The teacher will teach this lesson with the aid of:

Mathematical sets (compass, ruler, set square, protractor, pencil, eraser)
Charts or models of circles
Whiteboard and marker
Multimedia projection of circle illustrations (if available)

Rationale for the Lesson

This lesson is essential because understanding circles, their properties, and constructions helps students develop problem-solving, technical drawing, and spatial reasoning skills needed in mathematics, engineering, and design.

Prerequisite/Previous Knowledge

Pupils are familiar with basic plane shapes and have practiced drawing simple geometric figures with compass and ruler in earlier lessons.

Lesson Content/Board Summary

Circle

A circle is a closed curve in which all the points are equidistant from a fixed point called the center.

Parts of a Circle

Every circle has specific parts which help in its study and construction.

The following are the parts of a circle:

Center – the fixed point from which all points on the circle are equidistant.
Radius – a line from the center to any point on the circle.
Diameter – a straight line passing through the center, touching two points on the circle.
Chord – a line joining two points on the circle but not necessarily passing through the center.
Arc – a part of the circumference of the circle.
Sector – a region bounded by two radii and an arc.
Segment – a region bounded by a chord and an arc.
Circumference – the boundary or perimeter of the circle.
Tangent – a straight line that touches the circle at one point only.
Normal – a line drawn from the center of the circle to meet the tangent at right angles.

Types of Circles

Circles can be grouped based on their size, position, or relationship with one another.

The following are types of circles:

Equal Circles – circles that have the same radius.
Unequal Circles – circles that have different radii.
Concentric Circles – circles that share the same center but have different radii.
Intersecting Circles – circles that cut across each other at one or more points.
Tangent Circles – circles that touch each other externally or internally at one point.

Construction of Tangents and Normals to a Given Circle

Tangents and normals can be drawn to a circle using a compass and ruler.

The following are steps in construction:

Draw a circle with a given radius and mark its center.
Choose a point on the circumference.
Draw a line from the center to the point – this is the radius.
Construct a perpendicular line at that point – this line is the tangent.
The radius drawn to the tangent at the point of contact is the normal.

Construction of Tangents to Two Equal and Unequal Circles

Tangents can also be drawn to touch two circles, either equal or unequal, externally or internally.

The following are steps:

Draw the two given circles with their centers marked.
For external tangents, join the centers of the two circles and construct parallel tangents touching both circles.
For internal tangents, draw a line between the centers and construct a tangent line that touches both circles internally.
Ensure accuracy with compass and ruler to achieve correct tangents.

Teaching Methods/Instructional Techniques:

Lecture, Discussion, Explanation, Demonstration, Group Work, Question and Answer, Practical Exercise

Instructional Procedures

To deliver this lesson, the teacher will adopt the following steps:

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: Teacher asks pupils to recall familiar objects like coins or wheels that resemble circles, then introduces the topic.
Pupils’ Activity: Pupils respond by naming objects and listening attentively.
Learning Point: Pupils are introduced to the topic and motivated to learn.

Step 2: Definition and Parts of a Circle

Time: 10 minutes
Teaching Skill: Explanation
Teacher’s Activity: Teacher defines a circle and explains its parts with charts and drawings on the board.
Pupils’ Activity: Pupils observe, take notes, and ask questions.
Learning Point: Pupils understand the definition and major parts of a circle.

Step 3: Types of Circles

Time: 8 minutes
Teaching Skill: Discussion
Teacher’s Activity: Teacher explains and gives examples of equal, unequal, concentric, intersecting, and tangent circles.
Pupils’ Activity: Pupils discuss in groups and share examples.
Learning Point: Pupils differentiate between the types of circles.

Step 4: Construction of Tangents and Normals

Time: 12 minutes
Teaching Skill: Demonstration
Teacher’s Activity: Teacher demonstrates how to construct tangents and normals to a given circle and to two equal and unequal circles using instruments.
Pupils’ Activity: Pupils practice the constructions individually and in groups.
Learning Point: Pupils acquire skills in constructing tangents and normals to circles.

Step 5: Note-Taking

Time: 5 minutes
Teaching Skill: Explanation
Teacher’s Activity: Teacher writes the board summary for pupils to copy into their notes.
Pupils’ Activity: Pupils copy the board summary neatly.
Learning Point: Pupils keep a written record of the lesson.

Step 6: Evaluation/Review

Time: 3 minutes
Teaching Skill: Questioning
Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

Mention three parts of a circle.
State two types of circles.
What is a tangent and a normal?
List the steps in constructing a tangent to a circle.
Pupils’ Activity: Pupils answer the questions orally.
Learning Point: Pupils demonstrate understanding of the lesson objectives.

Step 7: Conclusion

Time: 2 minutes
Teaching Skill: Reinforcement
Teacher’s Activity: Teacher summarizes the lesson and encourages practice of circle constructions at home.
Pupils’ Activity: Pupils listen attentively and ask questions where necessary.
Learning Point: Pupils consolidate their understanding of circles and their constructions.

Lesson Keywords

Circle – a closed curve where all points are equidistant from the center
Radius – line from the center to a point on the circle
Diameter – line through the center touching two points on the circle
Tangent – line that touches a circle at only one point
Normal – line from the center meeting the tangent at right angles

Differentiation

Slower learners are guided step by step in constructions, while faster learners attempt more complex tasks such as constructing tangents to unequal circles independently.

Note for teachers using this lesson plan

Ensure pupils use their mathematical sets correctly. Move around the class to check accuracy during construction. Reinforce neatness and precision in drawing circles and tangents.