Final answer:
To find the average length in millimeters, sum the measurements in inches and divide by the total count, then multiply by the conversion factor of 1 inch to 25.4 millimeters. The average length of the given measurements in millimeters is 518.16 mm.
Step-by-step explanation:
To calculate the average length in millimeters of the given lengths in inches (18.5 in, 20.75 in, 22 in, 21.25 in, and 19.5 in), we'll first need to add them together and then divide by the number of measurements, which is 5. We'll convert the average to millimeters by using the conversion factor that 1 inch is equal to 25.4 millimeters.
Sum of measurements = 18.5 + 20.75 + 22 + 21.25 + 19.5 = 102 inches
Average length in inches = Sum of measurements / Number of measurements = 102 / 5 = 20.4 inches
Then we convert the average in inches to millimeters:
Average length in millimeters = Average length in inches * Conversion factor = 20.4 * 25.4 = 518.16 mm
Therefore, the average length of the measurements in millimeters is 518.16 mm.