Cylinders a and b are similar solids. the base of cylinder a has a circumference of 4π units. the base of cylinder b has an area of 9π units. the dimensions of cylinder a are multiplied by what factor to produce the corresponding dimensions of cylinder b?

The formula for the circumference of a circle is
  C = 2π·r
or
  r = C/(2π)
The radius r of cylinder A is
  r = (4π)/(2π) = 2

The formula for the area of a circle is
  A = π·r²
or
  r = √(A/π)
The radius of cylinder B is
  r = √(9π/π) = 3

The dimensions of cylinder A must be multiplied by 3/2 to produce the corresponding dimensions of cylinder B.