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abcd is a trapezium such that ab is parallel to cd. ef is parallel to ab and cd such that ef divides trapezium in two equal areas. find ef |
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Answer» Answer: ABCD is trapezium in which AB∥DC. Then we have AB∥DC∥EF. Hence we have also trapezium ABFE and trapezium EFCD. Let AP be the PERPENDICULAR to DC and this INTERSECTS EF at Q. AQ will be perpendicular to EF. For △APD and △AQE we have EAAD=AQAP=2 This gives AP=2AQ i.e, AQ=QP Consider the area we have area ABCD= area ABFE+ area EFCD (21)AP×(AB+DC)=(21)AQ×(AB+EF)+(21)QP×(EF+DC) ⇒AP(AB+DC)=AP×2AB+AP×2EF+AP×2EF+AP×2DC ⇒AP×2AB |
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