Answer
$ 0.92$ square units
Work Step by Step
We know that $K=\frac{a^2sin(B)\sin(C)}{2\sin(A)}=\frac{b^2\sin(A)\sin(C)}{2\sin(B)}=\frac{c^2\sin(A)\sin(B)}{2\sin(C)}$ and also that the sum of the angles of the triangle is $180^o.$
Hence $C=180^o-40^o-20^o=120^o.$
Thus,
$K=\frac{2^2\sin(20^o)\sin(120^o)}{2\sin(40^o)}\approx 0.92.$
