The cross-sectional area of a hole is 725 cm². given that the area of a circle is a= πr², find the radiusof that hole.

Given the formula, A= πr², to find the radius, make r the subject of the equation.
                           r = √(A/π)
    where we know π= 3.142 corrected to 3 decimal places,
         our radius    r = √(725/3.142)
                              = √230.745
                              = 15.190cm