
Justice R. answered 09/11/20
Child Development Student & Writer Teaching to Multiple Intelligences
The mistake is the use of "feet."
Usually, when saying measurements in a sentence, we would say "feet" for a measurement that is 2 ft or longer. For example:
"It's fourteen feet long."
"I measured the diameter, and it came out to fourteen feet."
"All fourteen feet of it."
In all of these cases, the measurement is being used as a noun.
However, when a measurement is used as an adjective, "feet" becomes "foot." Here, "fourteen feet" is acting as an adjective to describe the "diameter."
So the correct phrase is "Well it's elliptical, with a fourteen foot diameter."