Double Math

# Angle and their Types

There are two types of geometry: 2D Geometry and 3D Geometry. They are all composed of points, lines, rays, and plane surfaces before classification. Angles are measurements between two lines or rays convergent at the same point.

## What are Angles?

An angle is formed by the combination of two rays with a common endpoint. An angle consists of two components, the sides, and the vertex. Sides can be classified as terminal sides (or vertical sides) or initial sides (or horizontal sides).

### Parts of Angle

• Vertex – The intersection of two arms.
• Arms – A vertex is formed by two straight lines.
• Angle – The angle between the initial and final position of a ray is defined by the rotation it undergoes at its endpoint.

Kindes of Angle

There are two Kindes of angles

1. Positive Angle
2. Negative Angle

Positive Angle

Positive angles are those that go counterclockwise.

Negative Angle

Negative angles are those that go clockwise.

Types of Angle

Acute Angle

An angle measure less than 90 degrees.

Right Angle

An angle is exactly 90 degrees.

Obtuse Angle

An angle whose measure is greater than 90 degrees and less than 180 degrees.

Straight Angle

An angle that is exactly 180 degrees.

Reflex Angle

An angle whose measure is greater than 180 degrees and less than 360 degrees.

Full Angle

An angle whose measure is exactly at 360 degrees.

## Angles are also sometimes classified based on their position, the direction of rotation, the sum of their pairs, or their transversal into the following types:

• Interior Angles
• Exterior Angles
• Positive Angles
• Negative Angles
• Complementary Angles
• Supplementary Angles
• Vertically Opposite Angles
• Alternate Interior Angles
• Alternate Exterior Angles
• Corresponding Angles
• Consecutive interior Angles

• Interior Angles

## Inside angles are those located inside a shape.

• Exterior Angles

## Exterior angles refer to those formed on the external surfaces of the shape.

### Complementary Angles

Complementary angles are formed when the sum of two angles equals 90°.  It is not necessary for the two angles to be equal in size in order to add up to 90°. For example, the two angles can be 45° and 45°.

### Supplementary Angles

The sum of two angles is equal to 180°, they are called supplementary. The two angles when added make up 180°. For example, 110° and 70° make up 180°.