How to solveit using Lagrangian Function????

Consider a circular sheet of paper cut as in the figure below. We would like to make a cone out of the circular paper. What should the angle o be such that the cone volume is max? Formulate the problem as an optimization problem and mention the necessary constraints. Then use the Lagrangian method to find the optimum angle. (Hint: You can first find the optimum circle radius R with respect to cone radius r). R Ih R e ᎡᎾ