Question 119
In the quadrilateral $ABCD$ point $E$ is the middle of the side $AB$, point $F$ is the middle of the side $BC$, point $G$ is the middle of the side $AD$. Turns out that the segment $GE$ is perpendicular to $AB$, and segment $GF$ is perpendicular to $BC$. Find the angle $GCD$ given $\angle ADC = 70^\circ$.