Identifying Angles in a Figure
1. What is an angle?
An angle is the amount of turning between two lines meeting at a point.
2. How are angles formed?
When 2 lines meet at a point, they form an angle at that point.
3. How do we denote angles?
We denote angle using the symbol ∠.
1. Ali bends a straw as below. Mark the angle formed by it.
![model diagram](/images/notes/P3AN_Identifying_1.png)
The bent straw (presented by the blue lines) forms an angle as marked by the red turning.
2. Following are examples of angles on objects we see everyday.
![model diagram](/images/notes/P3AN_Identifying_2.png)
On each object, the angles are marked by the yellow turning.
3. Here are some pairs of pencils placed in pairs.
Which of these pairs form angles?
![model diagram](/images/notes/P3AN_Identifying_3.png)
Pairs A, C and D form angles.
4. Study the angles below.
a. Which angle is the smallest?
b. Which angle is the greatest?
c. Arrange the angles in order, beginning with the smallest.
![model diagram](/images/notes/P3AN_Identifying_4.png)
a. The lines forming Angle Y have the smallest turning.
So, ∠Y is the smallest angle.
So, ∠Y is the smallest angle.
b. The lines forming Angle X have the greatest turning.
So, ∠X is the greatest angle.
So, ∠X is the greatest angle.
c. Beginning with the smallest, the angles can be arranged as below:
∠Y, ∠Z, ∠X
∠Y, ∠Z, ∠X
5. Rayan makes some shapes as shown below.
How many sides and angles does each shape have?
![model diagram](/images/notes/P3AN_Identifying_5.png)
Shape A has 3 sides and 3 angles.
Shape B has 4 sides and 4 angles.
Shape C has 5 sides and 5 angles.
Shape D has 6 sides and 6 angles.
Shape B has 4 sides and 4 angles.
Shape C has 5 sides and 5 angles.
Shape D has 6 sides and 6 angles.