<prompt> As per Haase rule, age of the fetus in last 5 months is-Square root of the lengthLength in mm5Length in cm5Length in mm7  <response>: Ans. is c i.e., Length in cm5 Rule of Haase : During the first five months of pregnancy the square root of the length gives the approx, age of the fetus in months. During last five months the length in centimeters is divided by five gives the age in months. 