Rhombus area

Find the area of the outer square and then take off the outer triangles 

There are three ways to calculate the area of a rhombus:

1. Multiply the lengths of the rhombus' two diaginals togother and then divide the result by two.
2. Multiply the base and the height of the rhombus together.
3. Use Trignometry,  Take the length of any side  of the rhombus and square it then multiple the result by the sine of one of the angles of the rhombus.

Here's the easy way: length*width

now the hard way: take off both triangles and put them together into a square and put it together with the rectangle to get it as length times width