Angles ( Definition, types and measures of angles)

Class: Basic 5

Subject: Mathematics

Topic: Angles ( Definition, types and measures of angles)

An angle is a point where two or more lines meet each other.

The unit for measuring angles is degree. A protractor is used in measuring and drawing angles.

Types of angles

1.) Acute angles: These are angles less than 90°. Examples are 21°, 45°, 60°, 78°, 83°, etc.

2.) Obtuse angles: These are angles greater than 90° but less than 180°. Examples are 95°, 110°, 127°, 169°, 172°, etc.

3.) Reflex angles: These are angles greater than 180° but less than 360°. Examples are 185°, 197°, 202°, 274°, 318°, 321°, etc.

4.) Complementary angles: are angles formed when two angles add up to 90°. For examples:

41° + 49° = 90°.

41° and 49° are complements to each other.

63° + 27° = 90°

63° and 27° are complements to each other.

5.) Supplementary angles: are angles formed when two angles add up to 180°. For example:

94° + 86° = 180°; Angle 94° is supplement to 86°.

123° + 57° = 180°.

123° and 57° are supplements to each other.

Exercises

Use a protractor to draw the following angles:

1.) 48°

2.) 125°

3.) 169°

4.) What is the complentary angle of 39°?

5.) The supplementary angle of 62° is ______________