# Maths Revision

Angles:

• An angle less than 90 is called an acute angle.
• An angle of 90 is called a right angle.
• An angle between 90 and and 180 is called an obtuse angle.
• An angle of 180 is called a straight angle.
• An angle between 180 and 360 is called a reflex angle.
• Angles on a straight line add up to 180.

Angles inside a triangle add up to 180. This can be shown by tearing a triangle into 3 pieces, with a corner in each. Join the corners together to make a straight line. Because there are 180 on a straight line there must be 180 in a triangle.

• An angle is an amount of turn measured in degrees.
• Make sure you know this…

## Similar Mathematics resources:

See all Mathematics resources »See all Angles resources »

# Maths Revision

Angles:

• An angle less than 90 is called an acute angle.
• An angle of 90 is called a right angle.
• An angle between 90 and and 180 is called an obtuse angle.
• An angle of 180 is called a straight angle.
• An angle between 180 and 360 is called a reflex angle.
• Angles on a straight line add up to 180.

Angles inside a triangle add up to 180. This can be shown by tearing a triangle into 3 pieces, with a corner in each. Join the corners together to make a straight line. Because there are 180 on a straight line there must be 180 in a triangle.

• An angle is an amount of turn measured in degrees.
• Make sure you know this…