Angles are where two lines meet and measure the amount of turn. They are measured in degrees using a protractor. There are five main types of angles: acute angles are less than 90 degrees; right angles are exactly 90 degrees; obtuse angles are greater than 90 degrees but less than 180 degrees; a straight line is 180 degrees; and reflex angles are greater than 180 degrees.

1. Angle Facts
17 January, 2023
Objectives: To be able to name angles correctly
To be able to estimate and measure angles accurately

2. What is an angle ?
• Angles are where two lines meet.
• Angles are a measure of the amount of turn.
Angles measure the
amount of turn. We
use the curved line
to show this
The two lines meet here
An ANGLE

3. How do we measure angles?
Angles are measured using a
protractor
We measure angles in degrees
or o

4. Right Angles
• When two lines meet and form a perfect ‘L’
shape we call this a right angle .
• A right angle is 90o in size
Examples

5. Straight Lines
• A straight line is like turning through
two right angles .
• A straight line is 180o in size
Examples

6. Acute Angles
• An angle less than 90o in size is called
an acute angle
Examples

7. Obtuse Angles
• An angle more than 90o but less than
180o in size is called an obtuse angle
Examples

8. Reflex Angles
An angle more than 180o in size is called a
reflex angle
Examples

9. To recap, the 5 main types of angle are :
TOYS
Acute
Less than
90º
TOYS
Right
angle
90º
TOYS
Obtuse
More than
90º but less
than 180 º
TOYS
Straight
Line
180º
TOYS
Reflex
More than 180 º