Final answer:
The gerbil is 204 mm or 20.4 cm in length, as its body and tail are each 102 mm long and there are 10 mm in a centimeter.
Step-by-step explanation:
The correct answer is that Chris's gerbil is 204 mm or 20.4 cm in length. The gerbil's tail is 102 mm long, which is equivalent to 10.2 cm, since there are 10 mm in a centimeter.
Given that the tail's length is the same as the body length, we simply double the length of the tail to get the total length of the gerbil. Therefore, 102 mm for the tail plus 102 mm for the body equals 204 mm. To convert millimeters to centimeters, we divide by 10, thus 204 mm is 20.4 cm.
To convert the length of the gerbil's tail from millimeters to centimeters, we divide the length by 10 since there are 10 millimeters in a centimeter. Therefore, the length of the gerbil's tail in centimeters would be 102 mm ÷ 10 = 10.2 cm.