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

ALSO NEED HELP ON THIS!

A rectangle with length of 18 feet and width of 6 feet. A diagonal cuts the rectangle into two halves. One of the triangular halves is shaded.

2(18 + 6) = 48
fraction 1 over 2(18 + 6) = 12
fraction 1 over 2(18 × 6) = 54
2(18 × 6) = 216

Which equation can be used to calculate the area of the shaded triangle in the figure below ALSO NEED HELP ON THIS A rectangle with length of 18 feet and width class=