Classifying Angles

An angle is formed by two rays or line segments that intersect.

There are several types of angles, classified according to their angle measurements.

Interior angle of a polygon: formed when two sides of the polygon meet.

Exterior angle of a polygon: formed by extending one of the sides of the polygon. 

Image of a polygon

 

Acute angle
(between 0° et 90°)

 

Right angle
(90°)

 

Obtuse angle
(between 90° et 180°)


Straight angle
(180°)

 

Reflex angle
(between 180° et 360°)

 

Complete angle
(360°)

 

Zero angle
(0°)

These angles can be seen in many of the objects surrounding us.

The clock’s hands point to 3:15 a.m. and form a zero angle (0o).

Picture

Several geometric figures are defined by the fact that they contain a right angle.

Picture

The clock’s hands can form an obtuse angle, just like the sides of some shapes.

Picture

Vertical or horizontal lines contain straight angles.

Picture

Exercises

Exercise

Angle Names and Measures

Mathematics SecondaryNaN, NaNSec.1-2
Exercise

Classifying Angles

Mathematics SecondaryNaN, NaNSec.1-2