Q7 of 35 Page 311

Sumit and Reba have taken two cupper wire having same length. Sumit bent the wire in the form of a rectangular shape of which length and breadth are 48 cm. and 40 cm. But Reba bent the copper wire with same length in the form of a circle. Let us see by calculating which will cover maximum place between the rectangle drawn by Sumit and circle drawn by Reba.

Perimeter of the rectangular shape figure formed by wire = 2(l + b)


Where, l = length and b = breadth of rectangular figure


Perimeter = 2(48 + 40) = 2 × 88 = 176 m


⇒The length of the wire used for making a circle = 176m


Perimeter of circle = 2πr where r is the radius of circle


⇒2πr = 176


⇒


Area of rectangular shape = l × b = 48 × 40 = 1920 m2


Area of circular shape = πr2, where r is the radius of circle


⇒


= 2464 m2


Since the area enclosed by circular shape is more, wire bend as circle covers maximum place.


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