Scalene Triangle

If all the three sides of a triangle are different, then it is known as scalene triangle. In a scalene triangle all three angles are also different.

Isosceles triangle 

If any two sides of a triangle are same, then triangle is known as isosceles triangle. In an isosceles triangle two angles opposite to the equal sides are equal.

Height of this triangle = \(h\), where \(h = \sqrt {{b^2} - \frac{{{a^2}}}{4}} \)

Equilateral triangle

If all the three sides (or three angles of a triangle) are same, then the triangle is known as equilateral triangle. In equilateral triangle each angle is equal to 60°. Suppose side of the equilateral triangle is \(a\), then

Area of the triangle =\(\frac{{\sqrt 3 }}{4} \times {a^2}\)