We are asked to determine the area of a rhombus given the measure of its diagonals. To do that we will use the following formula:
[tex]A=\frac{d_1\times d_2}{2}[/tex]Replacing the values of the diagonals:
[tex]A=\frac{(8)(10)}{2}[/tex]Solving the operations:
[tex]A=\frac{80}{2}=40[/tex]Therefore, the area is 40 square kilometers.
