TRIANGLES AND ANGLES

TRIANGLES

All triangles have 3 sides and 3 angles which always add up to 180°.
Triangles are classified in 2 ways:

1)   By the number of equal sides they have:
  • Scalene - all 3 sides have different lengths
  • Isosceles - 2 sides have equal lengths
  • Equilateral - all 3 sides are equal

 

2)  By the types of angles they have:
  1. Acute triangle - all 3 angles are acute (less than 90°)
  2. Right triangle - has one right angle (a right angle = 90°)
  3. Obtuse triangle - has one obtuse angle (an obtuse angle is greater than 90° and less than 180°).