Lesson Notes By Weeks and Term - Junior Secondary 2

Triangles 2

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TERM – 1ST TERM

WEEK NINE

Class: Junior Secondary School 2

Age: 13 years

Duration: 40 minutes of 5 periods each

Date:

Subject: BASIC TECHNOLOGY

Topic:   TRIANGLES 2

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

  1. Circumscribe a circle to a triangle
  2. Inscribe a circle to a triangle
  3. Escribe Circle to a Triangle.

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers,

demonstration, videos from source

INSTRUCTIONAL MATERIALS:   Videos, loud speaker, textbook, pictures,

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION

TEACHER’S ACTIVITY

STUDENT’S

ACTIVITY

STEP 1

INTRODUCTION

The teacher highlight the procedures for circumscribing triangle and guide students to circumscribe a triangle

Students pay

attention

STEP 2

EXPLANATION

Teacher highlight the procedure for inscribing a circle and guide students to inscribe a circle.

Students pay

attention and

participate

STEP 3

DEMONSTRATION

Teacher highlight the procedure for escribing a circle and guide students to escribe a circle.

Students pay

attention and

participate

STEP 4

NOTE TAKING

The teacher writes a summarized

note on the board

The students

copy the note in

their books

 

NOTE

 TRIANGLES 2

Construction of Various Types of Triangles

  1. Circumscribing a circle to a triangle

Procedure

  1. Draw the perpendicular bisectors of the sides.
  2. Taking point O as the centre, draw a circle which touches each vertex of the triangle.
  3. The distance OA, OB and OC is said to be the circumradius. Hence, the required circumcircle has a circumcentre at O.

 

  1. Inscribing a circle to a triangle

Procedure

  1. Draw a given triangle ABC
  2. Bisect any two angles of the triangle. The bisecting lines will intersect at O, which is the centre of the inscribed circle.
  3. Draw a perpendicular line to any side from O to meet the side at D.
  4. With centre O and a radius OD, draw the inscribed circle.

 

  1. Escribing Circle to a Triangle

Procedure

I. Draw a triangle ABC

II. Plot the exterior angles for the angles B and C of the triangle

III. Draw an angle bisector of the constructed exterior angles. Mark the crossing point of the bisector as O. Point O is the centre of the escribed circle.

IV. Plot a perpendicular OD from point O to line AB, or a perpendicular OI to line AC. The plotted perpendicular lines will be the radii of the escribed circle.

V. Finally draw a circle with the centre at point O and a radius of OD.

The plotted circle will be escribed of triangle ABC

EVALUATION: 1. What does it mean to escribed a circle?

  1. How do you circumscribe a circle in to a triangle?

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively