A trapezoid has parallel bases of length 8 and 14, and a height of 6. What is its area?

The area of a trapezoid is the average of the bases times the height: $A=\frac{1}{2}(b_1+b_2)h=\frac{1}{2}(8+14)(6)=\frac{1}{2}(22)(6)=66$, choice J. You can check by thinking of the average width as $11$ and the height as $6$, which gives $11\cdot6=66$. Choice G ($132$) leaves out the factor of $\frac{1}{2}$, computing $(8+14)(6)$. Choice H ($84$) is $14\cdot6$, treating the trapezoid as a rectangle with the longer base. Choice F ($44$) is $(8+14)\cdot2$, which does not relate to the height at all.