Condition for intersection h=Lsin(0)/2>X Geometric implication ALSIna P=S/(d/2/2) S1=L2 d/2 L/2 兀/20q h x d Condition for intersection: h=Lsin(q)/2 > x Geometric implication: P = SI /(d/2 p/2) SI = L/2 x d/2 L/2 p/2 q x=Lsin(q)/2 I