## Thinking Mathematically (6th Edition)

$\frac{1}{2}$bh
The area, A, of a triangle with height h and base b is given by the formula $\frac{1}{2}$bh. The area of a parallelogram is used to obtain a formula for the area of a triangle. The area of the parallelogram is A= bh. The diagonal in the parallelogram divides it into two triangles with the same size and shape. This means that the area of each triangle is one-half that of the parallelogram.