A circular wire of radius 7cm is bent to form a rectangle whose sides are in the ratio 4 : 7 what is the area of the rectangle so formed?

radius = 7cm

circumference of circle = perimeter of rectangle = $$2\pi r$$ = $$2\times\frac{22}{7}\times 7$$ = 44cm

sides of rectangle are in the ratio = l : b = 4 : 7

let length = 4x 

     breadth = 7x

perimeter = 2(l+b) =44

                  2(4x+7x)=44

                  22x=44

                  x = 2

length = 4x = $$4\times2$$ = 8

breadth = 7x = $$7\times2$$ = 14

area of reactangle = $$l\timesb$$ =  $$8\times14$$ = $$ 112  cm^2 $$