No, it is not imagery.
Imagery would tell you how he looks specifically, these are all general observations. You cannot imagine him in a detailed manner with this info. Is he blond? Is he a brunette? Does he have pale skin? If we can't make an image in our mind, then it's not imagery. Imagery consists of SPECIFIC details. For example, imagery would be, "His eyes were a crystal blue, as if they were made of water. It seemed like you could jump right into them and swim for hours."
Simile, it compares two unlike things using like or as
I didn't actually understand the question but I will try to solve it.
Length of ribbon = 3 ft
Total number of small pieces = 8
So, length of each piece = 3/8 = 0.375 ft
