Question 273256
if you are talking about the circumference of the circle, then the equation is:


c = 2*pi*r


When c = 135, this formula becomes:


135 = 2*pi*r


divide both sides of this equation by 2*pi to get:


r = 135/(2*pi) which makes r = 21.48591732


rounded to the nearest 2 decimal places, that becomes 21.49.


If you are talking about the area of the circle, then the equation for that is:


a = pi*r^2


When a = 135, this formula becomes:


135 = pi*r^2


divide both sides of this equation by pi to get:


42.97183463 = r^2


take square root of both sides of this equation to get:


r = sqrt(42.97183463) = 6.555290584


rounded to the nearest 2 decimal places, that becomes r = 6.56,