MATHEMATICS
topic: angles
What is an angle : An angle is a point where two lines meet .
PARTS OF AN ANGLE
HOW TO MEASURE ANGLES ON A PROTRACTOR. WATCH THE VIDEO BELOW
Press this link to practice measuring angles on a protractor
Angles on a Clock . Every hour on a clock is 30 degrees
Watch the video below .
1. Complementary Angles
Definition:
Two angles are complementary if the sum of their measures is 90 degrees.
Key Point:
They do not have to be next to each other, but together they always total 90°.
Example:
If one angle is 65°, the other is:
90° − 65° = 25°
2. Supplementary Angles
Definition:
Two angles are supplementary if the sum of their measures is 180 degrees.
Key Point:
They may form a straight line when placed together, but they can also be apart.
Example:
If one angle is 110°, the other is:
180° − 110° = 70°
Angles Around a Point
Definition:
The angles that meet at a single point add up to 360 degrees.
Key Point:
These angles can be of any size but must completely surround the point.
Example:
If three angles around a point are 90°, 120°, and 80°, the missing angle is:
360° − (90° + 120° + 80°) = 70°