Date: September 16- 20, 2019
Grade:
11
Duration:
3 × 80 minutes
Topic:
Construction
Sub-topics:
Constructing unique triangles
Specific Objectives:
On the successful completion of the lesson, students should be able to:
1. Construct a unique triangle given:
a) Three sides
b) Two sides and an included angle
c) One side and two angles.
2. Be adequately prepared for class by having the required geometric instruments.
3. Work quickly to complete given tasks.
Instructional Materials:
1.
2.
3.
4.
Text: Mathematics: A Complete Course Vol. 2 by R. Toolsie.
Protractor
Compass
Ruler
Content Summary:
Constructing a Unique Triangle given Three Sides
Question 1: Using a ruler and compasses only, construct triangle ABC with AB = 6.5cm, AC =
4cm and BC = 5cm. measure and state the length of angle ABC.
Constructing a Unique Triangle given Two Sides and the Included Angle
Question 2: Using a ruler and compasses only, construct the triangle PQR, with PQ = 4.9cm, QR
= 3.6cm and angle PQR = 120º. Measure and state the length of PR.
Constructing a Unique Triangle given One Side and Two Angles
Question 3: Using a ruler and compasses only, construct the triangle LMN, with LM = 4.9cm,
angle L = 45º and angle M = 30º. Measure and state the magnitude of angle LNM.
Evaluation 1:


Complete activities from the text Mathematics: A Complete Course Vol 2- pages 744745; questions 26-30, 37-40.
Complete attached worksheet.
Evaluation 2:
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