ANGLES

An acute angle is less than 90º

A right angle is 90º

An obtuse angle is between 90º and 180º

A straight line angle is 180º

A reflex angle is between 180º and 360º

TRIANGLES

A right-angled triangle has one 90º angle

An isosceles triangle has two equal angles

An equilateral triangle has three equal angles, each of size 60º

A scalene triangle has three different angles