A circular jogging track of radius 10m has centre at the origin. A runner reaches the point B(6,8) on the track.
(i) Verify that B lies on the track.
(ii) Find the slope of the tangent to the track at B.
(iii) Determine the angle that this tangent makes with the positive x–axis, giving your answer correct to the nearest degree.
(iv) Obtain the Cartesian equation of the tangent line at B."