Find the perimeter of a quadrilateral abcd

then find the area of a quadrilateral abcd

By the pythagorean theorem we get that 2^2+4^2=20, so the diagonal side length is \sqrt{20}=2\sqrt{5}.

The perimeter is 4(2\sqrt{5})=8\sqrt{5}
The area is (2*4/2)*4=16

Google it that might work