In the interior of a rectangle ABCD we pick a point K for which AK=1, BK=2 and CK=3.
It seems to me that something is missing.
Obviously, sum of areas of triangles ABK and CKD = half the area of the rectangle.
Same also for the other two triangles. But we are missing one side (KD). Or not?
If we had this side, we could calculate both triangles using Heron's formula and then calculate the two sides of the rectangle.
Am I wrong?