"Feet" has no apostrophes.
Inches is shown by two apostrophes (").
The symbol for feet is one apostrophe, as in 15 feet = 15' The symbol for inches is two apostrophes, as in 15 inches = 15"
Plurals don't use apostrophes, so the first one is correct.
Two thirds of a yard is exactly two feet. One third of a yard is one foot; there are three feet to a yard.
"Feet" has no apostrophes.
Inches is shown by two apostrophes (").
The symbol for feet is one apostrophe, as in 15 feet = 15' The symbol for inches is two apostrophes, as in 15 inches = 15"
2 apostrophes mean inches, and one means feet. 6'5" means six feet and 5 inches
You don't. Apostrophes aren't use to make words plural. The plural of person is people. (One person, two people.) You don't need the apostrophe in apostrophes either.
Plurals don't use apostrophes, so the first one is correct.
The two types of apostrophes are the straight apostrophe ('), which is used to show possession or contraction, and the curly or typographic apostrophe (β), which is a more visually appealing version of the straight apostrophe.
Apostrophe has only one name. It's apostrophe. The plural is apostrophes.
The inch sign is two prime symbols (″), while the foot sign is one (′). In ordinary typing, single and double quotation marks or apostrophes may be substituted.
No words are contracted into apostrophes.
Look at your keyboard, and you can easy see this different kinds.
It's. But this can be it is and it has. The reader relies on context to know which one it is.