//Body is projected
//u be the velocity of projection and alpha the angle of projection
//then maximum height reached=((u^2)*(sind(alpha))^2)/(2*g)
//range=((u^2)*sind(2*alpha))/(g)
//in this case 
//Range=3*maximum height reached
//thus
alpha=atand(4/3)  //degree
printf("\n alpha=%.2f degree",alpha)