What is the area of the rhombus shown below?

So hmmm the diagonals of a rhombus, bisect each other angles, and thus, they cut each other in halves, and they're also perpendicular to each other, check the picture below

so, they end up forming 4 equal triangles

so, just get the area of each of the triangles, and sum them up, that's the area of the rhombus

or the area of one of the triangles, and multiply it times 4, same thing