In a rhombus, all the side lengths are 10 and one of the angles is equal to 120 degrees. Find the area of the rhombus.

Hint:

If a triangle has sides 10 and 10 with the angle between them x degrees

The area of area of the triangle will be 1/2 * 10 * 10 * sin(x)

Draw the rhomubus, that will help you see the relevance.