Please solve it : Complete solution$($A to Z$)$

Example $2\mathrm{.}23$: A road bend which deflects $80$ is to be designed for a maximum speed of $100$ km per hour, a maximum centrifugal ratio of $\frac{1}{4}$ and a maximum rate to change of acceleration of $30c\frac{m}{se{c}^3},$ the curve consisting of a circular arc combined with two cubic spirals. Calculate $($a$)$ the radius of the circular arc, $($b$)$ the requisite length of transition $($c$)$ the total length of the composite curve and $($d$)$ the chainages of the beginning and end of transition curve and of the junctions of the transition curves with the circular arc if the chainage of the P$.$I. is $42862$ m $.$