Two bodies are projected from the same point with equal speeds in such directions that they both strike the same point on a plane whose inclination is β. If  α be the angle of projection of the first body with the horizontal the ratio of their times of flight is:

.Let α' be the angle of projection of the second body range=R=u2g cosβsin(2α−β)−sinβ  sin(2α−β)=sin(2α'−β)   or   2α'−β=π−(2α−β) ⇒α'=π2−α−βtime of flight=T=2usin(α−β)gcosβ   and  T1=2usin(α1−β)gcosβ divide the two equations TT1=sin(α−β)sin(α1−β) TT1=sin(α−β)sinπ2−(α−β)−β TT1=sin(α−β)sinπ2−α TT1=sin(α−β)cos α