Question 21
A circle $\omega_1$ of radius 8 is internally tangent to a circle $\omega_2$ of radius 25 at a point T. A line through the centre O of $\omega_2$ is tangent to $\omega_1$ at S. A chord AB of $\omega_2$ perpendicular to OS is tangent to $\omega_1$ at Q. Find the length of AB.