How to use trapezoid area calculator?

According to the formula for the calculations of the trapezoid area, it requires height(h), short base(a) and long base(b).

Example :

Height(h) = 6

Short Base(a) = 16

Long Base(b) = 8

Formula :

$$A\;=\;\frac{a+b}{2}\;h$$

$$A\;=\;\frac{16+8}{2}\;6$$

$$A\;=\;\frac{24}{2}\;6$$

$$A\;=\;12\;*\;6$$

$$A\;=\;72\;\text{cm}^2$$