Math 4 - Quarter 1 - Week 1 - Kinds of Angles

Learning
Competencies
The learners will be able to:
1. Illustrate different angles
(right, acute, and obtuse)
using models.
2. Measure and draw angles
using a protractor.

Learning
Objectives
At the end of the lesson the
learners will be able to:
1. Identify and differentiate
right angles from other types
of angles.
2. Define a right angle as a
90-degree angle.

Understanding
Right Angles
DAY 1

Real-life Examples Of Right
Angles

“RIGHT ANGLE HUNT"
Find objects around the
classroom that have right
angles and explain why
those angles are right
angles.

HANDS-ON ACTIVITIES:
Create your own objects
with right angles.
For example, you can design
and build a small bookshelf
using cardboard and identify
the right angles you've
incorporated.

REAL-LIFE EXAMPLES:
Find real-life examples of
right angles.
Identify the "L" shape and
explain why it's a right angle.

DISCUSSION:
Why right angles are
important in everyday life,
architecture, and navigation?

REVIEW:
• What do we call the space
between two lines that meet?
• How do we measure angles?
• What's the unit we use?
• If two lines are at a 90degree
angle, what term do we use?

REVIEW:
• Can you think of an object around
you that has right angles? What is
it?
• How many degrees are in a right
angle?
• When you make an 'L' shape with
your fingers, are they
perpendicular?
• Can you give an example of an
angle you might see at home or

REVIEW:
• What shape has four right angles?
Can you draw it?
• If you fold a piece of paper and
create a corner, what have you
made?
• When you cross two pencils to
form a 'T' shape, what do we call
the way they meet?

- At 9:00, the minute and hour hands of the
clock form an angle which measures 90˚.
- This angle, like all angles which measure
90˚, is called a right angle.
RIGHT ANGLES

- An angle that forms a square corner is a right angle.
- A right angle measures 90.
- Angle PIA is a right angle.

Form your bodies into a right angle
by bending their arms at the elbow to
create an "L" shape.

•Create your own right
angles by joining two
pieces together.
HANDS-ON CONSTRUCTION:
Work In Pairs Or Small
Groups
Materials:
like straws
cardboard
craft sticks

Construction Of A Right
Angle Using A Protractor.

• Summarize the
characteristics of right
angles in your own words.
GENERALIZATIONS
AND ABSTRACTIONS

• Find and photograph real-
world right angles in the
environment.
ASSIGNMENT:

Learning
Objectives
1. Define and recognize acute
angles.
2. Identify acute angles in
different contexts.

Angles are measures of how
much one direction deviates from
another. In simpler terms, they help
us understand how much something
is turned or tilted. Small angles
are angles that are not very wide or
open. They are often less than 45
degrees.

Have you ever looked at a
clock and noticed the long and
short hands pointing at
different numbers?

Those hands create small
angles to show us the time! Small
angles are like tiny turns or tilts.

Imagine you have a pencil on your table.
It's not standing straight up, and it's not
lying flat either – it's at a little angle. That's a
small angle!
We see small angles in lots of everyday
things, like stairs, swings, and even when we
walk up a hill. These small angles help us tell
time, move around, and even build strong
and cool things.
So, small angles might be small, but
they're super important!"

ACUTE ANGLE HUNT
Your mission is to find
triangles that have angles
smaller than a corner but
bigger than a flat line.

CREATIVE CORNER:
Draw your own
triangles and color in the
acute angles.

REVIEW:
• What is an acute angle?
• How many degrees are in a right
angle?

"ACUTE ANGLE SEARCH"
Look for real-life
examples of acute angles
around the classroom.
When you find an example,
you can draw and label it.

- This is between 0˚ and 90˚ The angle here,
like all other angles which measure
between 0˚ and 90˚, is called an acute
angle.

- An angle less than a right angle is an acute angle.
- An acute angle measures less than 90 degree.
- Angle SEB is an acute angle.

"ACUTE ANGLE HUNT"
Sort the cards and
identify which ones are
acute angles (less than 90
degrees).

How acute angles can be
measured with a protractor?

• Why acute angles are
important in geometry and
real-world applications?
GENERALIZATIONS
AND ABSTRACTIONS

Categorize the pictures whether it is
an
acute or not.

• Create your own set of
acute angle flashcards
for review.
ASSIGNMENT:

Learning
Objectives
1. Define and distinguish
obtuse angles from other
types of angles.
2. Identify and measure
obtuse angles accurately.

Seatwork:
Identify whether the following is a right,
acute or obtuse angle.
1. An angle more than 90˚
2. An angle less than 90˚
3. An angle which is exactly 90˚
4. 5.

Real-life Examples Of Obtuse
Angles

Investigating Obtuse
Angles
DAY 3

• Obtuse angles are angles
that measure more than 90
degrees but less than 180
degrees.
Introduction to Obtuse Angles:

Hands-On Activities:
Create their own obtuse
angles using paper, protractors,
or even their own bodies.

Real-World Scavenger Hunt:
Identify objects or shapes
around you that have obtuse
angles.

This is between 90˚ and 180˚ The angle here,
like all other angles which measure between
90˚ and 180˚, is called an obtuse angle.

- An angle greater than a right angle is an obtuse
angle.
- An obtuse angle measures more than 90 but less
than 180.
- Angle AGL is an obtuse angle.

Angle Art:
Draw your own obtuse angle,
making it as wide as you can.
Imagine your obtuse angle is a
slice of something yummy!

Measuring an Obtuse Angle:
• Draw an obtuse angle on the
screen and place the
protractor's center at the vertex
(corner) of the angle.
• Align the baseline of the
protractor with one side of the
angle.
• The protractor will show the
measurement of the angle.

Drawing an Obtuse Angle:
• Draw your own obtuse angles.
• Use the interactive protractor to
measure and draw the angle.

Characteristics of the different angles:
• Acute angles are smaller than
90 degrees.
• Right angles are exactly 90
degrees.
• Obtuse angles are larger than
90 degrees.

Sorting Activity:
a. Distribute the angle cards
randomly among the learners or
groups.
b. Look at each angle, measure its
degree using a protractor, and then
decide which category it belongs
to: acute, right, or obtuse.
c. Place the angle cards on the
corresponding sorting mat or
board.

• Give real-world situations
where obtuse angles are
encountered.
GENERALIZATIONS
AND ABSTRACTIONS

• Create a visual poster
displaying different types of
angles and their properties.
ACTIVITY:

Learning
Objectives
At the end of the lesson the learners
will be able to:
1. Define what an angle is and its
components.
2. Identify and differentiate between
acute, obtuse, and right angles.
3. Explain the concept of a protractor
and its use in measuring angles.

Introduction to
angles and their
characteristics.
DAY 4

• What do you know
about geometric
shapes and angles?

Show-and-Tell Activity:
• Identify the shape or shapes you
see in the picture.
• Describe the shapes and count the
sides and corners.

• Can you find something around the
classroom or at home that has a
similar shape?

• Identify where you can see the
right, acute, and obtuse angles in
the following pictures.

Real-Life Angle Hunt: Small
groups
• List of objects or scenarios to find and
measure angles: doors, windows,
corners of tables, books and blackboard
• Find and measure a right angle (90
degrees).
• Find and measure an acute angle (less
than 90 degrees).
• Find and measure an obtuse angle (more
than 90 degrees).
Share their findings and describe
where they found each type of
angle.

Term Introduction:
• Angle: A shape formed when two
lines meet or cross each other.
• Vertex: The point where the two
lines meet in an angle.
• Arms: The two lines that form an
angle.

• Acute Angle: An angle that is
smaller than a right angle (less
than 90 degrees).
• Obtuse Angle: An angle that is
larger than a right angle but
smaller than a straight angle
(between 90 and 180 degrees).

• Right Angle: An angle that looks
like the corner of a square and
measures 90 degrees.
• Protractor: A tool we use to
measure angles in degrees.

Three Main Types Of Angles:
• Acute Angle:
An acute angle is
smaller than a right
angle.
It's like a "tiny“
angle.

• Right Angle:
Right angle is
exactly 90 degrees.
It looks like the
corner of a book or
a square.

• Obtuse Angle:
An obtuse angle is wider than a right
angle.
Examples like an open book or a clock at
a specific time.

How To Identify And Classify Angles Based
On Their Measurements?

• Summarize the key
concepts about angles
and protractors.
Generalizations
And Abstractions

Learning
Objectives
1. Measure angles accurately
using a protractor.
2. Draw angles of specific
degrees using a protractor.

Measuring and Drawing
Angles with a
Protractor
DAY 5

Strategy for Precise
Angle Measurement:
1. Steady Protractor:
Put your protractor on a flat and
stable surface, like a table or a desk.
This helps to keep it steady while you
measure.
2. Center Match:
Make sure the middle dot of the
protractor (that's the center) fits right
on the corner point of the angle. This
is really important for getting the right

3. Side Line-Up:
Put one side of the angle right along
the straight line at the bottom of the
protractor. This is the starting point for
measuring.
4. Read Carefully:
Look where the other side of the angle
crosses the protractor's circle. Read
the number right where it touches.
Read it
carefully, like reading a number in
your math problems.

5. Inner or Outer Numbers:
If your angle is smaller than a corner
(90 degrees), use the numbers inside
the circle. If it's bigger, use the
numbers outside.

1. Imagine you have a protractor. One
of its sides is labeled "0 degrees" and
the other side is labeled "180
degrees." If you measure an angle and
the second side crosses the "90
degrees" mark on the protractor, what
type of angle is it? Write the answer.
Answer the following questions:

2. Pretend you're explaining angles
and
protractors to a friend who doesn't
know about them. Use the word
"measure" and
"degrees" in your explanation. For
example: "We use a protractor to
measure angles. The degrees tell us
how big the angle is."

What type of angle is it?
Is it acute, right, obtuse, or straight?
Problem 1: Identifying Angle
Types
Look at the angle below.

Problem 2: Measuring an Acute Angle
Using a protractor, measure the size
of the angle marked by the vertex
letter "D."

Problem 3: Comparing Angles Compare
the two angles below. Which angle is
bigger, the one marked by "E" or the one
marked by "F"?

Draw These Angles On Your Own:
Degree Measurements
(30°, 90°, 120°)

a. How did you find drawing angles
using a
protractor?
b. Why is it important to follow the
steps accurately when using a
protractor?
c. Can you think of real-life situations
where precise angle measurement is
crucial?
Answer the following questions:

• Summarize the steps for
measuring and drawing
angles with protractors.
Generalizations
And Abstractions

Math 4 - Quarter 1 - Week 1 - Kinds of Angles

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