Hello rn5a Originally Posted by

**rn5a** I am having problems doing the following (please have a look at the attached figure):

Find the area of a rhombus whose side is 15 cm long while one of the diagonals is 24 cm long. Here AD=15 cm & AC=24 cm.

(Hint: Find OD using Pythagoras theorem)

Thanks,

Ron

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

Area of rhombus = $\displaystyle \tfrac12$ product of the lengths of the diagonals

The 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 $\displaystyle \tfrac12$ 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