Question 121
Let $AB$ be a diameter of the circle $k$. Let $t$ be the tangent to $k$ at the point $B$ and be $C, D$ two points on $t$, so that $B$ is between $C$ and $D$. The straight lines $AC$ or $AD$ cut $k$ again in the points $E$ or $F$. The straight lines $DE$ or $CF$ cut $k$ again in the points $G$ or $H$. Prove that the routes $AG$ and $AH$ have the same length.