What is the area of the quadrilateral?

[Monokonos]

View attachment 7882
https://gyazo.com/55afe69c0f00bff85a3a9c53bd353b42

Sorry for the really poorly drawn and lit picture...

Basically this quadrilateral is drawn inside a circle whose middle point is O. Here is the info I was given

KL = 18
LM = 24
KN = NM

What I need to find out is the area of KLMN.

What I did there split the quadrilateral into 2 with a diameter. I found out the length of that with the pythagorean theorem. It was 30. So logically the area of that triangle is 24x18/2 = 225.

But how do I find out the volume of the second triangle? I know it's really simple but I just can't figure it out...

 

[skeeter]

If KM is a diameter, then triangle KNM is isosceles with base KM = 30 and height ON = 15 $\implies$ area of triangle KNM is 225.

triangle KLM is inscribed in a semicircle, therefore angle L is 90 degrees ...

area of triangle KLM is 216