Question 443139
As you know the area of the circle given by the formula:{{{A=(pi)r^2}}}, where r 

is the radius of the circle.Substitute and get:{{{254.34=3.14*r^2}}} =>

{{{r=sqrt(254.34/3.14)}}}, and {{{D=2r=2*sqrt(81)=2*9=18 cm }}}, where D is the 

diameter of the circle.