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ICSE-VIII-Mathematics

20: Area of Trapezium and a Polygon Class 8 Maths

with Solutions - page 4
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  • #18
    The length and the breadth of a rectangular field are in the ratio 5:4 and its area is 3380 m2. Find the cost of fencing it at the rate of ₹75 per m.
    Ans : Ratio in length and breadth = 5 : 4
    Area of rectangular field = 3380 m2
    Let length = 5x and breadth = 4x
    5x × 4x = 3380
    ⇒ 20x2 = 3380
    ⇒ x2 = 3380/20 = 169 = (13)2
    ⇒ x = 13
    Length = 13× 5 = 65 m
    Breadth =13× 4 = 52 m
    dlt23851564568179465016">Perimeter = (l + b) = 2× (65 + 52) m = 2× 117 = 234 m
    Rate of fencing = ₹ 75 per m
    Total cost = 234× 75 = ₹ 17550