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1. Lesson Plan in Geometry
Prepared By: Merry Joy B. Ordinario
I. Objectives
At the end of the lesson, the students are expected to:
1. Define the following terms
i. Complementary angles
ii. Supplementary angles
iii. Adjacent angles
iv. Vertical angles
v. Linear pair
2. Identify the relationships of angles
II. Learning Task
A. Topic: Relationships of Angles
B. Mathematical Concept
In geometry, like any other branches of Mathematics, there are some problems
where the relationship of angles is significant.
C. Mathematical Process Skills
1. Solving Skills
2. Critical Thinking
D. Value Focus
1. Patience
2. Cooperation
III. Instructional Materials
A. Visual Aids
1. Cartolina
2. Marker
3. Chalk
B. Reference
Fundamentals of Mathematics 1 by Arellano, et.al pp. 110 – 111
High School Subject for Self Study Volume 3 by Murray pp. 1020-1022

2. IV. Lesson Proper
Teachers’ Activity Students’ Activity
I. Prayer
II. Introduction
Good morning class.
III. Motivation
Hep Hep Horray (Angle Version)
Mechanics: The teacher points out one
student at a time to act the kind of angle
(right, acute, and obtuse angle) the
teacher says. Failure to do the act will
result to elimination. Game ends when
only one remains undefeated.
IV. Review
Just a short review before proceeding to
our lesson, what are the different kinds of
angle?
Correct. What do you call an angle that
measures exactly 90º?
Who can draw in the board an example of
a right angle?
Very good. Now take a look at this angle.
What kind of angle is this?
How can you say it’s an acute angle?
That’s correct. Now who can draw on the
Good morning ma’am.
There are three different types of angles
based on measurements; these are acute
angle, right angle, obtuse angle.
It’s a right angle ma’am.
It’s an acute angle ma’am
Because it measure less than 90º.

3. board a 130º angle?
What kind of angle is a 130º angle and
why?
V. Lesson Proper
Take a look at this figure. How many
angles can you see in this figure?
Correct. We have ∠2 named as ∠DBC
and ∠1 named as ∠CBA. What can you
notice on these two angles? Do they have
the same end point?
What is their common side?
These two angles are called adjacent
angles. Adjacent angles are two angles
that have the same point or vertex and a
common side between them.
Now take a look at this figure. How
many angles can you see?
This figure shows two intersecting lines
at point A. these two intersecting lines
form four angles namely ∠1, ∠2, ∠3 and
∠4. What can you say about ∠1 and ∠3?
It’s an obtuse angle because it measures
greater than 90º but less than 180º.
There are two angles.
Yes, they have a common end point or
point B.
The common side is 𝐷𝐵⃗⃗⃗⃗⃗⃗ .
There are 4 angles.

4. Correct. If angles are opposite to each
other and are formed by two intersecting
lines they are called vertical angles. Now
what can you say about ∠1 and ∠2?
∠1 and ∠2 are both forming an adjacent
line and they are as well supplementary
that’s why they are called linear pair.
Please draw on the board a 50º and a 40º.
What kind of angles do we have here?
Very good. The same as integers, we can
also add two angles using its measure.
Who can add these two angles?
When the sum of the two angles
measures 90º we call them
complementary angle.
Now take a look at these two angles.
What kind of angles do we have here?
And what is the total measure of these
two angles?
These angles are called supplementary
angles because the sum of two angles
measures 180º.
Now get a ¼ piece of pad paper and
answer these questions.
They are opposite to each other.
They are adjacent to each other.
The two angles are acute angles.
50º + 40º = 90º
We have an acute and obtuse angles.
110º + 70º = 180º

5. V. Evaluation
Direction: Answer the following questions on the test paper only.
I. Write true if the statement is true, and false if otherwise.
______1.Supplementary angles measures 90º.
______2.Angles that has a common endpoint is called complementary angle.
______3.Vertical angles are opposite to each other and have a common endpoint.
______4. Linear pairs are supplementary and adjacent.
______5. Complementary angles measures 180º
II. Base the answer on the given figure below
A. Name the vertical angles.
1. _____ and _____
2. _____ and _____
B. Name the linear pairs
1. _____ and _____
2. _____ and _____
3. _____ and _____
4. _____ and _____