Triangles (JSS 2- Basic Technology Lesson Note: First Term, Week Eight)

Week Eight

Subject: Basic Technology
Class: J.S.S Two
Week of the First Term: 8th Week
Topic: Triangles

Sub-topics:

• Definition of Triangles
• Types of Triangles
• Parts of Triangles

Instructional Objectives

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

1. Define a triangle and describe its key characteristics.
2. Identify and categorize different types of triangles based on their sides and angles.
3. Illustrate and label the parts of a triangle, including vertices, sides, and angles.

Entry Behaviour

Pupils should already know the basic concepts of geometric shapes and have an understanding of points and lines.

Instructional Materials

1. Textbook: Foundations of Sci. & Tech for Junior Secondary School Book 2 by Chris Ijiyemi.
2. Visual aids: Diagrams of various triangles and their parts.
3. Flashcards: Cards showing different types of triangles (e.g., equilateral, isosceles, scalene).

Reference Materials

Ijiyemi, C. (2016). Foundations of Sci. & Tech for Junior Secondary School Book 2. Metropolitan Publishers. Lagos.

Adeyemi, M.B., Ukadike, M., & Danladi, S. (2015). Wabp Basic Technology For Junior Secondary School Book 2. West African Book Publisher. Lagos.

Content

Triangles

Definition of Triangles: A triangle is a three-sided polygon formed by connecting three non-collinear points (vertices) with straight line segments (sides). The sum of the interior angles of a triangle is always 180 degrees.

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Types of Triangles:

By Sides

1. Equilateral Triangle: All three sides are equal in length, all three angles are equal, measuring 60° each.
2. Isosceles Triangle: Two sides are of equal length, and the third side is different, the angles opposite the equal sides are also equal.
3. Scalene Triangle: All three sides are of different lengths, all angles are different as well.

By Angles

1. Acute Triangle: All three angles are less than 90°.
2. Right Triangle: One angle is exactly 90°, the side opposite the right angle is called the hypotenuse, and the other two sides are called the legs.
3. Obtuse Triangle: One angle is greater than 90°. the other two angles are acute (less than 90°).

Parts of Triangles:

1. Vertices: The points where the sides of the triangle meet.

• Example: In triangle ABC, points A, B, and C are the vertices.

2. Sides: The straight line segments that connect the vertices.

• Example: In triangle ABC, if side aaa is opposite vertex A, then side bbb is opposite vertex B, and side ccc is opposite vertex C.

3. Angles: The measures formed between two sides of a triangle at a vertex.

• Example: In triangle ABC, ∠A\angle A∠A, ∠B\angle B∠B, and ∠C\angle C∠C are the angles at vertices A, B, and C, respectively.

4. Altitude: A perpendicular segment from a vertex to the line containing the opposite side.

• Example: The altitude from vertex A to side BCBCBC creates a right angle at the intersection point.

5. Median: A line segment drawn from a vertex to the midpoint of the opposite side.

• Example: The median from vertex A to side BCBCBC will meet side BCBCBC at its midpoint.

6. Bisector: A line that divides an angle into two equal parts.Example: The angle bisector of ∠A\angle A∠A divides it into two equal angles.

Step 1: Introduction

Lesson Presentation (Step-by-Step Procedure)

Others removed.