math
posted by maya .
I have to find the area of a kite. I am only given part of the longest diagonal (12 cm) and half of the other diagonal (9 cm). I know the formula is diagonal 1 times diagonal 2 times 1/2. I have the length for one diagonal which is 18 cm b/c 9+9. How can find the length of the short part of the long diagonal (12). Any help is appreciated

I think we are missing information
Was there an angle given? 
I think so too; there wasn't an angle give

The way the question stands, the "bottom" of the kite could be any length along the missing part of the diagonal.
The angle at the shorter diagonal's end wasn't a rightangle ? 
Sorry, my question is worded confusingly. so, there are two diagonals on the kite. the shortest diagonal is 18 cm total. the longest diagonal has only part of the length given which is 12 cm, I need to find the length of the other part. is there any way that I can post a picture of the figure?