The area (K) of a quadrilateral can be found by

the diagonals are p & q

In this case, from the data give:

p = 2+3 = 5 & q = 4+2 = 6

You have given the three sides of a triangle: 2,2,3

Use the cosine law to compute

Probably easier (since is isosceles)

Compute and , then plug them into the equation above.