a. To get the feel of an angle through observation of objects and by paper folding:
b. Able to learn the names of angle like acute, obtuse and right angle:
c. Able to identify right angles in the environment:

__Introduction of Angles__

** **

__a. To get the feel of an angle through observation of objects
and by paper folding:__

Bridges,
buildings, cell phone towers, wings of planes, bicycles, windows doors and
things around us have angle in them.

__Angle:__

The figure formed by two rays/ with a common
point is called an angle.

**Teacher:**
What does this the picture show?

**Ramu:**
This picture shows an angle. Does angle have name sir?

**Teacher:**
Yes. Angles have names. Can you see two line segments in this picture? Read the
names of that.

**Ramu:** Sir, This angle has
two line segments. They are BA and BC.

**Teacher:**
Which is the common point of the two line segments?

**Ramu: **B
is the common point.

**Teacher:**
These two line segments make an angle. Common point B is vertex. BA&BC are
arms of the angle.

**Ramu : **Then
how can we name the angle in the picture?

**Teacher:**
An angle is mentioned by three alphabet. The centre letter of the angle denotes
the vertex.

**Ramu:**
Then, ABC is the name of the angle. Am I right sir?

**Teacher: **Yes,
We should mention the angle as angle ABC.

**Ramu:**
Sir, can we write angle CBA instead of angle ABC.

**Teacher:**
Surely. Angle ABC and Angle CBA are same. We use this symbol ∠ for angle.

So we can write angle ABC as ∠ ABC.

Angle between ground and stair case

Angle between ladder and ground

Angle
between branches of a tree

Angle in a electric pole

Angle in a bicycle

Angle in a house

Angle
in a Clock

__Find:__

In this picture, mark the angles
formed inside and outside by using colour pencils.

** **

__Project:__

Collect some pictures
having angles, and paste the same in a chart.

Draw some angles by
using pencil and show it to your teacher.

__Activity__

Look at the angles formed by your elbow and draw them as stick
picture and show it to your teacher. Please share it with your friends and
check.

** **

**Word and meaning:**

The word angle came from
the Greek word “Angilos”. It means curved and not straight. Ankle is the place
where knee and leg foot is joined.

__b. Able to learn the names of angle like acute, obtuse and right
angle:__

We
can create the various angles by combining the two wooden frames. Let us see
the picture given below, from these shape we can find the types of angles.

**Write the angles generated in the following
items. (Obtuse angle, acute angle, right angle)**

** **

**Try this**

__c. Able to identify right angles in the
environment:__

Ram is trying to cut a rectangular piece
of wood, from a wooden board. Ram used a tool to cut sides of the rectangle. We
call this device as set square.

We can see two set squares in a Geometry
Box. It has 90° each.

**Examples of right
angles:**

**Do Yourself: **Draw 5 objects with right angle.

** **

**Classify the angles as acute, obtuse and right angle.**

**Try these**

**Classify the following angles**

**30°,
45°, 60°, 90°, 120°, 130°, 170°, 75°**

**Answer:**

Acute angle: **30°, 45°, 60°, 75°**

Right angle:** 90°**

Obtuse angle:** 120°, 130°, 170°**

** **

**Observe the following pictures and write the name of the angles
in their box.**

** **

**Activity 1**

Draw right angle, acute
angle and obtuse angle by tracing.

** **

__Project (Art and Craft)__

1. Form the angles
acute/obtuse/right angle by cutting/folding the papers and paste it in a chart.

2. Write the names of the
flowers or animals (or) birds in English capital letter and mention the angles
in it.

Tags : Geometry | Term 1 Chapter 1 | 5th Maths , 5th Maths : Term 1 Unit 1 : Geometry

Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail

5th Maths : Term 1 Unit 1 : Geometry : Introduction of Angles | Geometry | Term 1 Chapter 1 | 5th Maths

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