A hollow cone is cut by a plane parallel to the base and the upper portion is removed. If the curved surface of the remainder is 98 of the curved surface of wholecone, find the ratio of the line-segment into which the cone's altitude is divided by the plane
l1,h1,r1 are length,height,radius if a short cone
ll1=hh1=rr1 ∴ C.S.A of the smaller cone =91× C.S.A of given cone ∵ C.S.A. of the remaining portion =98× C.S.A. of given cone ⇒πr1l1=91πrl⇒rlr1l1=91 or hh1×hh1=91 ⇒(hh1)2=91 or hh1=31 h1=31h∴h2=h−h1=h−31h=32h Hence, h2h1=21.