Types of Triangles

Types of Triangles

Types of triangles by its interior angles (acute triangle, right triangle, obtuse triangle) and by its sides(scalene triangle, isosceles triangle, equilateral triangle).

By Its Interior Angles

Acute Triangle: Its interior angles are all acute angles. Right Triangle: It has a right angle. Obtuse Triangle: It has an obtuse angle.

Acute Triangle:
its interior angles are all acute angles.
0 < m∠(purple) < 90

Right Triangle:
it has a right angle.
m∠(blue) = 90

Leg:
the sides that are adjacent to the right angle

Hypotenuse:
the side that is opposite to the right angle

Obtuse Triangle:
it has an obtuse angle.
90 < m∠(red) < 180

By Its Sides

Scalene Triangle: It has no congruent sides. Isosceles Triangle: It has two congruent sides (& angles). Equilateral Triangle: It has three congruent sides (& angles).

Scalene Triangle:
it has no congruent sides.

Isosceles Triangle:
it has two congruent sides (& angles).

Leg:
congruent sides

Base:
the side that is adjacent to both congruent angles

Equilateral Triangle:
it has three congruent sides (& angles).