Through a point located inside a triangle, lines parallel to the sides of the triangle are drawn.

These lines divide the triangle into three triangles and three quadrilaterals. Let $a, b$ and $c$ be the heights parallel to the sides of these three triangles. Find the height parallel to them in the original triangle.
The specified quadrilaterals are parallelograms, and the three indicated triangles are similar. The sum of their sides, perpendicular to the drawn heights, is equal to the side of the original triangle. Therefore, the sum of the corresponding heights is equal to the height of the original triangle.

## Answer

$a+b+c$.

## Problem