Question

if a wire bent in the shape of square then its area is 81 centimetre square then the same wire bent in the shape of circle what is the area of semicircle

Answer 1

side^2=81
side=9cm
perimeter =9*4=36
circumference =36=2πr
r=5.7cm
area=(πr^2)/2
on substitute you find the ans

Answer 2

area of the square is 81cm...so each of its side=9cm.
so,perimeter of the square is 36cm.........that means length of the wire or circumference of the circle is 36cm
circumference of a circle=2πr
so radius of the circle will be 63/11cm.
area of a circle=πrsquare
or,22/7×63/11×63/11=1134/11cm2or 103.09091cmsquare...
approximately, 103cm square is the area of the circle and area of the semicircle =103/2...or51.5cm...
HOPE,,,It helps u....