TERM – 2^{ND} TERM
WEEK ONE
Class: Senior Secondary School 1
Age: 15 years
Duration: 40 minutes of 5 periods each
Date:
Subject: Technical Drawing
Topic: INSCRIBED AND CIRCUMSCRIBED CIRCLE
SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to
I.) Inscribing a circle to a given triangle
II.) Circumscribing a circle to a given 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 explains the meaning of inscribing and circumscribing to the students |
Students listens attentively to the teacher |
STEP 2 EXPLANATION |
Teacher guide students to inscribed and also circumscribe a circle to a given triangle respectively. |
Students exhibit attentiveness and active engagement |
STEP 3 NOTE TAKING |
The teacher writes a summarized note on the board |
The students copy the note in their books |
NOTE
INSCRIBED AND CIRCUMSCRIBED CIRCLE
Inscribing a circle to a given triangle
A circle can be inscribed inside a triangle if the center of the circle lies at the intersection of the triangle's angle bisectors, and the radius of the circle is the distance from the center to any of the triangle's vertices. An Inscribed circle is a circle that is drawn inside a triangle touching all three sides.
To draw an inscribed circle, we need to bisect TWO inside angles,
drop a perpendicular and draw the circle inside the triangle.
Circumscribing a circle to a given triangle
A circle can be circumscribed around a triangle if the center of the circle lies at the intersection of the perpendicular bisectors of the triangle's sides, and the radius of the circle is the distance from the center to any of the triangle's vertices.A Circumscribed circle is a circle that is drawn outside of a triangle and touches all three vertices.
To draw a circumscribed circle, we need to bisect TWO sides and draw the circle outside the triangle touching vertices A, B and C.
EVALUATION: 1. Given a triangle, what's the difference between the inscribed circle of the triangle and the circumscribed circle of the triangle?
QPR = 60° (Show all construction lines).
(i) Find the lengths PR and QR.
(ii) Inscribe a circle in the triangle PQR.
(iii) Name the triangle PQR.
CLASSWORK: As in evaluation
CONCLUSION: The teacher commends the students positively