{"id":11538,"date":"2022-07-18T14:35:34","date_gmt":"2022-07-18T09:05:34","guid":{"rendered":"https:\/\/mathemerize.com\/?p=11538"},"modified":"2022-07-18T14:35:38","modified_gmt":"2022-07-18T09:05:38","slug":"in-the-figure-ps-is-the-bisector-of-triangle-pqr-prove-that-qsover-sr-pqover-pr","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/in-the-figure-ps-is-the-bisector-of-triangle-pqr-prove-that-qsover-sr-pqover-pr\/","title":{"rendered":"In the figure, PS is the bisector of \\(\\triangle\\) PQR. Prove that \\(QS\\over SR\\) = \\(PQ\\over PR\\)."},"content":{"rendered":"
Given<\/strong> : PQR is a triangle and PS is the bisector of \\(\\angle\\) QPR meeting QR at S.<\/p>\n \\(\\therefore\\)\u00a0 \\(\\angle\\) QPS = \\(\\angle\\) SPR<\/p>\n To Prove<\/strong> : \\(QS\\over SR\\) = \\(PQ\\over PR\\)<\/p>\n Construction<\/strong> : Draw RT parallel to SP to cut QP produced at T.<\/p>\n Proof<\/strong> : Since PS || TR and PR cuts them, hence we have :<\/p>\n \\(\\angle\\) SPR = \\(\\angle\\) PRT\u00a0 \u00a0 \u00a0 …….(1)\u00a0 \u00a0 \u00a0 \u00a0(alternate angles)<\/p>\n and \\(\\angle\\) QPS = \\(\\angle\\) PTR\u00a0 \u00a0 \u00a0 \u00a0 \u00a0………(2)\u00a0 \u00a0 \u00a0(corresponding angles)<\/p>\n but,\u00a0 \\(\\angle\\) QPS = \\(\\angle\\) PTR\u00a0 \u00a0 \u00a0 \u00a0 ………(3)\u00a0 \u00a0 \u00a0 (given)<\/p>\n \\(\\therefore\\)\u00a0 \\(\\angle\\) PRT = \\(\\angle\\) PTR\u00a0 \u00a0 \u00a0 \u00a0[From (1) and (2)]<\/p>\n \\(\\implies\\)\u00a0 PT = PR\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0……….(3)\u00a0 \u00a0 \u00a0 \u00a0 (sides opposite to equal angles are equal)<\/p>\n Now, in \\(\\triangle\\) QRT, we have :<\/p>\n SP || RT\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0(by construction)<\/p>\n \\(\\therefore\\)\u00a0 \\(QS\\over SR\\) = \\(PQ\\over PT\\)\u00a0 \u00a0 \u00a0 \u00a0(by basic proportionality)<\/p>\n or\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \\(QS\\over SR\\) = \\(PQ\\over PR\\)\u00a0<\/strong> \u00a0 \u00a0 \u00a0 \u00a0 \u00a0(from 3)<\/p>\n","protected":false},"excerpt":{"rendered":" Solution : Given : PQR is a triangle and PS is the bisector of \\(\\angle\\) QPR meeting QR at S. \\(\\therefore\\)\u00a0 \\(\\angle\\) QPS = \\(\\angle\\) SPR To Prove : \\(QS\\over SR\\) = \\(PQ\\over PR\\) Construction : Draw RT parallel to SP to cut QP produced at T. Proof : Since PS || TR and PR …<\/p>\n