Hello rn5aFollowing my answer to your previous post, the other way of finding the area of a rhombus is to use the formula:

Area of rhombus = product of the lengths of the diagonalsThe reason this formula works is because the diagonals of a rhombus are perpendicular, thus dividing the rhombus into four right-angled triangles. The area of each triangle is base x height; when you multiply this by 4, you'll find that you get the formula above.

So, use the hint you're given to find OD (which is half the length of one of the diagonals), and then multiply it by the length of the other diagonal.

Grandad