Which equation can be used to calculate the area of the shaded triangle in the figure below?

A rectangle with length of 14 feet and width 4 feet. A diagonal cuts the rectangle into two halves. One of the triangular halves is shaded.

fraction 1 over 2(14 × 4) = 28
2(14 + 4) = 36
fraction 1 over 2(14 + 4) = 9
2(14 × 4) = 112