Sounds like the situation in the sketch below...
There is a theorem that says the angle (BAD) formed by a tangent (AB) and a secant (AD) to a circle (O) is half the difference of the intercepted arcs (BD and BD'):
[tex]m\angle BAD=\dfrac{110^\circ20'-69^\circ40'}2=40^\circ40'[/tex]
Triangle BAD is a right triangle, so
[tex]m\angle ADB=90^\circ-m\angle BAD=49^\circ20'[/tex]