Exploring Triangles: Definitions, Types, and Their Unique Parts Basic Technology JSS 2 First Term Lesson Notes Week 9
Basic Technology JSS 2 First Term Lesson Notes Week 9
Subject: Basic Technology
Class: JSS 2
Term: First Term
Week: 9
Age: 12 years
Topic: Triangles
Sub-topic: Definition and Types, Sketch Types of Triangles and Parts of a Triangle
Duration: 40 minutes
Behavioural Objectives:
By the end of the lesson, students should be able to:
- Define triangles and identify their types.
- Sketch different types of triangles.
- Describe the parts of a triangle.
Keywords:
- Triangle: A three-sided polygon.
- Acute Triangle: All angles are less than 90°.
- Obtuse Triangle: One angle is greater than 90°.
- Right Triangle: One angle is exactly 90°.
- Equilateral Triangle: All sides and angles are equal.
Set Induction:
The teacher asks students to recall shapes they learned previously and highlights the importance of triangles in construction and design.
Entry Behaviour:
Students should already know basic geometric shapes and have an understanding of angles.
Learning Resources and Materials:
- Sketching paper
- Pencils and rulers
- Triangle models
- Visual aids showing different triangles
Building Background/Connection to Prior Knowledge:
Students have previously learned about angles and polygons, providing a foundation for understanding triangles.
Embedded Core Skills:
- Critical thinking
- Artistic skills in sketching
- Collaborative skills through group activities
Learning Materials:
- Geometry textbooks
- Reference books on polygons
Reference Books:
- Lagos State Scheme of Work
- Basic Technology for Junior Secondary Schools by NERDC
Instructional Materials:
- Triangle models (physical or digital)
- Whiteboard and markers
Content:
I. Definition of Triangles
- Triangle: A polygon with three sides and three angles.
- Formula for Area: Area = 1/2 × base × height.
II. Types of Triangles
- By Sides:
- Equilateral Triangle: All sides are equal.
- Isosceles Triangle: Two sides are equal.
- Scalene Triangle: All sides are different.
- By Angles:
- Acute Triangle: All angles are less than 90°.
- Right Triangle: One angle is exactly 90°.
- Obtuse Triangle: One angle is greater than 90°.
III. Parts of a Triangle
- Vertices: The corners of the triangle.
- Sides: The lines connecting the vertices.
- Angles: The space between two sides at a vertex.
IV. Sketching Types of Triangles
- Equilateral Triangle: Draw three equal sides and equal angles.
- Isosceles Triangle: Draw two equal sides and one different side.
- Scalene Triangle: Draw three sides of different lengths.
- Acute Triangle: Ensure all angles are less than 90°.
- Right Triangle: Draw one 90° angle.
- Obtuse Triangle: Draw one angle greater than 90°.
15 Fill-in-the-Blank Questions:
- A triangle has ______ sides.
a) Four
b) Three
c) Two
d) Five - An equilateral triangle has ______ sides that are equal.
a) No
b) Some
c) All
d) Two - A right triangle has one angle that measures ______.
a) 45°
b) 90°
c) 60°
d) 30° - The corners of a triangle are called ______.
a) Sides
b) Vertices
c) Angles
d) Bases - An isosceles triangle has ______ equal sides.
a) No
b) One
c) Two
d) Three - A triangle with all angles less than 90° is called an ______ triangle.
a) Acute
b) Obtuse
c) Right
d) Isosceles - The area of a triangle can be calculated using the formula: Area = ______.
a) Base + Height
b) 1/2 × Base × Height
c) Base × Height
d) 1/3 × Base × Height - A triangle with one angle greater than 90° is called an ______ triangle.
a) Acute
b) Right
c) Obtuse
d) Equilateral - The sides of a triangle connect at the ______.
a) Base
b) Angle
c) Vertex
d) Height - The sum of all angles in a triangle is ______ degrees.
a) 180
b) 90
c) 360
d) 270 - A scalene triangle has ______ equal sides.
a) One
b) Two
c) Three
d) No - The ______ is the longest side in a right triangle.
a) Hypotenuse
b) Base
c) Height
d) Side - Triangles can be classified by their ______ and sides.
a) Length
b) Width
c) Angles
d) Color - A triangle that has two equal angles is called an ______ triangle.
a) Equilateral
b) Isosceles
c) Right
d) Scalene - A triangle can be drawn using a ______ and a ruler.
a) Protractor
b) Compass
c) Marker
d) Pencil
15 FAQs with Answers:
- What is a triangle?
A triangle is a three-sided polygon. - How do you classify triangles?
They can be classified by sides (equilateral, isosceles, scalene) and angles (acute, right, obtuse). - What are the parts of a triangle?
The parts include vertices, sides, and angles. - How do you find the area of a triangle?
Use the formula: Area = 1/2 × base × height. - What is an equilateral triangle?
It is a triangle with all sides and angles equal. - What makes a right triangle special?
It has one angle that measures exactly 90°. - Can a triangle have two obtuse angles?
No, the sum of angles in a triangle must equal 180°. - What does scalene mean?
It refers to a triangle with all sides of different lengths. - How can I sketch a triangle?
Use a ruler to draw three lines connecting at three points. - What is the significance of the vertices in a triangle?
They are the corners where the sides meet. - How do you measure the angles in a triangle?
Use a protractor to measure each angle. - What type of triangle has two equal sides?
An isosceles triangle. - What is an acute triangle?
A triangle where all angles are less than 90°. - Can you give an example of a real-life triangle?
The triangular shape of roofs or sails. - Why are triangles important in construction?
They provide stability and strength in structures.
Presentation Steps:
Step 1:
The teacher revises the previous topic about angles and their types.
Step 2:
The teacher introduces the new topic by explaining the definition of triangles and their types.
Step 3:
The teacher allows pupils to contribute, demonstrating their understanding by sketching different types of triangles.
Teacher’s Activities:
- Demonstrate how to sketch different types of triangles.
- Guide students in identifying parts of triangles.
- Discuss practical applications of triangles.
Learners’ Activities:
- Practice sketching various types of triangles.
- Label the parts of their drawn triangles.
- Work in pairs to compare their sketches.
Assessment:
- Define a triangle.
- List the types of triangles based on sides.
- Sketch an equilateral triangle.
- Explain the characteristics of a right triangle.
- How do you find the area of a triangle?
- Identify the parts of a triangle.
- Describe a scalene triangle.
- What is the sum of angles in a triangle?
- How many sides does a triangle have?
- Why are triangles important in design and construction?
Conclusion:
The teacher goes around to mark the students’ work and provides feedback on their understanding of triangles.