$ABCD$ is a trapezium with $AB < CD$ and $AB$ parallel to $CD$. $\Gamma$ is a circle inscribed in $ABCD$, such that $\Gamma$ is tangent to all four sides. If $AD = BC = 25$ and the area of $ABCD$ is $600$, what is the radius of $\Gamma$?

Your answer seems reasonable.
Find out if you're right!