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The shape of a farm is a quadrilateral. Measurements taken of the farm, by naming its corners as P, Q, R, S in order are as follows. l(PQ) = 170 m, l(QR)= 250m, l(RS) = 100 m, l(PS) = 240 m, l(PR) = 260 m.Find the area of the field in hectare ( 1 hectare =10,000 sq.m) |
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Answer» Solution :- PQRS is a quadrilateral. PQ = 170 m, QR 250 m, RS = 100 m, PS = 240 m, PR = 260 m This question will be solved through Heron's formula of area of TRIANGLE. There are two triangles in the quadrilateral PQRS. These are Δ PQR and Δ PSR In Δ PQR, PQ = 170 m, QR = 250 m and PR = 260 m Semi perimeter (s) = (a + b + c)/2 (170 + 250 + 260)/2 ⇒ 680/2 s = 340 m Area of triangle PQR = √340*(340 - 170)*(340 - 250)*(340 - 260) ⇒ √340*170*90*80 ⇒ √416160000 ⇒ 20400 sq m In Δ PSR, SR = 100 m, PS = 240 m and PR = 260 m S = (a + b + c)/2 ⇒ (100 + 240 + 260)/2 ⇒ 600/2 ⇒ 300 m Area of triangle Δ PSR = √(300)*(300 - 100)*(300 - 240)*(300 - 260) ⇒ √300*200*60*40 ⇒ √144000000 = 12000 sq m Area of the quadrilateral PQRS = Area of Δ PQR + Area of Δ PSR ⇒ 20400 + 12000 = 32400 sq m Area in hectares = 32400/10000 = 3.24 hectares Answer. |
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