Divide A Triange into a 5 triangle of equal Area.

The answer is pretty simple and straight forward.
Area of a triangle is 1/2 x (base) x (height).

So divide the base into 5 segments and join the segment end points to the vertex opposite to the base.
Area of the triangles now is 1/2 x (base/5) x (height) = Area of the original triangle / 5.