If you know the lengths of the diagonals — d1 and d2 — of a kite, finding the area is simple with the formula above.

Otherwise, you can use this method:

$$$ Area = a * b * sin(c) $$$

Where $$a, b$$ are the lengths of two unequal sides, and $$c$$ is the angle between them ($$sin$$ being the trignometric function sine https://en.wikipedia.org/wiki/Sine)