Just do b*h/2 for all the triangles.
I think it's D but I'm not %100 sure
Answer:

Step-by-step explanation:
Area of a rhombus is the product of the length of the diagonals divided by two.
Length of one diagonal is 8 units and the other diagonal is 16 units
Area is given by

The area of the rhombus is 
Another approach is the diagonals have created 4 triangles where the base and is height is either 4 units long or 8 units long so the area of the rhombus would be the area of the 4 triangles.

Create a graph to locate the intersection of the equations. The intersection of the system of equations is the solution.
(18,269.82)
Answer:
8x-9y=31
Step-by-step explanation: