its very useful to mathematics teachers to how plan in the class room..

1. GMR V DAV PUBLIC SCHOOL,RAJAM
Lesson Plan
Class: IX Subject: Mathematics
Chapter Name: Lines and Angles
TOPIC : ANGLE SUM PROPERTY OF TRIANGLE
Objectives :
PrerequisiteKnowledge:
In this chapter students are able to recall
1. Lines and Angles: Class VII
2. The Triangles and its Properties: Class VII
3. Introduction to Euclid's Geometry: Class IX
In this chapter students are able to ….
1. Explain the terms ‘line’, ‘ray’, ‘line segment’, ‘collinear points’, ‘intersecting lines’
and‘parallel lines’
2. Describe the different types of angles
3. Explain the terms ‘adjacent angles’, ‘linear pair of angles’, ‘complementary
angles’, ‘supplementary angles’ and ‘vertically opposite angles’
4. To understand the angles formed by a transversal …corresponding angles,
alternative angles, sum of same side interiors supplementary
5. To understand the lines which are parallel to the same line are parallel to each
other.
6. To learn how to prove that the sum of three angles of a triangle is 1800
PROCESS:
1.ShortDescription Of the Lesson
In this chapter, for motivated part learners will revise basic geometrical terms
and definitions like Explain the terms ‘line’, ‘ray’, ‘line segment’, ‘collinear points’,
‘intersecting lines’ and ‘parallel lines’. They will also learn about the linear pair
axiom. Thelearners will recall knowledge about the different types of anglesand
the angles formed by a transversal on a pair of parallel and intersecting lines.
Moreover, they will be taught to prove theoremsrelated to lines, angles and
triangles. Students were clearly taught regarding types of angles, pair of angles,
Angles made by transversal , students are taught the properties of triangle like
sum of all angles in a triangle 1800 by the following teaching aids.

2. 2. Teaching Aids :
a. Introduction to lines and angles
b. Pair of angles& Angles made by transversal

3. Activity on Angle sum property :
Material required : colour pens, chart and colour glazed papar,
pair of scissors, fevi stick gum..
Process:
1. Consider a triangle
2. Cut off angles from the vertices.
3. Arrange cut off angles on a straight line
Result:
We will come to know the sum of all angles in triangle is 180.

4. D. Supplemental Activities:
Ask the learners to read how properties of lines and angles areused by
professionals.For example, engineers and architectsapply the properties of lines and
angles while making designs or blueprints for buildings.
ExpectedOutcome:
After studying this chapter, learners will be able to describe basicgeometrical terms and
definitions. They will also be able toexplain the linear pair axiom. The learners will be
able to solveexercises based on the different types of angles and the anglesformed by a
transversal on a pair of parallel and intersecting lines and properties related to triangles.
Moreover, they will be able to prove related to lines, angles and triangles. Students can
calculate the problems using the theorem “Angle sum property of triangle”
Values:Students are able to develop power of imagination, concentration, Intellectual
development and problem solving..
Assessment : Class test and extra sums from Teach Next Module and refreshers.
Assignment: solve the following work sheet
GMR VARALAKSHMI DAV PUBLIC SCHOOL
WORK SHEET (LINES &ANGLES)
MATHEMATICS- CLASS 9
Time: 10Min., Marks: 10M
I. Solve the following problems:
1. In triangle ABC, ĿA = 440,
find ĿB and ĿC? 1m
2. The vertical angle of an isosceles triangle is 1000
, Find its base angles? 1m
3. If the measure of an angle is thrice the measure of its supplementary angle, then find the
measure of angle 1m
4. In the given figure, if l | | m and a : b = 2 : 3 then find the value of y. 1m
5. The measure of an angle is 8 times its complement. Find the angles. 2m
6. The angles of triangle are in the ratio 3 :4 :5. Find the measure of each angle. 2m
7. In the given figure, POS is a line. Find ĿQOR. 2m
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