There are two circles with center A and D. The tangent line touches both point B and C. The given measurements are enough to solve for the missing value and the solution is shown below: AB=9 BC=26 DC=8 Solve for the measurement of AC which the hypotenuse of legs AB and BC by Pythagorean theorem: c²=a²+b² c²=9²+26² c=AC=27.51 Solve for angle of A sin A=26/27.51 A=70.93° Finally, we solve for the length of AD using SOH sin 70.93°=AD/27.51 AD=26 The answer is 26.