Let r be the radius and y be the perpendicular distance from the centre to chord C2, meaning the distances to C1 and C3 are (y - d) and (y + d). Using the property that half a chord length equals the square root of (radius squared minus distance squared), we get three equations: r squared - (y - d) squared = 100, r squared - y squared = 64, and r squared - (y + d) squared = 16. Adding the first and third equations gives 2(r squared) - 2(y squared) - 2(d squared) = 116, and since (r squared - y squared) equals 64 from the second equation, we substitute to find that d squared equals 6. Substituting d squared and y squared back allows us to solve for the radius, yielding r = 5 times the square root of 65, all divided by 3.