Question

A wire when bent in the form of a square, encloses an area of 441cm^2. If the same wire is bent to form a circle, what will be the radius of the circle so formed?

Answer 1

let side of the square = a cm
i) area of the square formed by the wire = 441cm²
a² = 441cm²
a²=(21cm)²
a= 21 cm----(1)
perimeter of the square = 4a= 4*21 =84 cm----(2)
ii)circumference of the circle formed by same wire = perimeter of the square
⇒2πr = 84     [here r is radius of the circle]
⇒2*22/7 r =84
⇒r = (84*7)/(2*22)
r=147/11cm