"Foot" is singular, and "feet" is plural.
There are 12 inches in a foot.
One mile is 5,280 feet, so the difference is 5,279 feet or 63,348 inches.
1 yard = 3 feet
A linear foot is distance. A square foot is area. One square foot is the area of some square tiles used on floors. Ten square feet is 1 foot x 10 feet or 2 feet x 5 feet. Don't confuse this with a 10 foot square which is 10 feet by 10 feet which equals 100 square feet.
One square foot is 1 foot X1 foot, 1 foot square is also 1 foot x 1 foot. The only difference is that in 100 square feet it would be 10 x 10 or 5 x 20 etc but in a 100 foot square it is 100 feet X 1 foot only.
A running foot (also called a linear foot or just foot) is a measure of distance in 1-dimensional space. A cubic foot is a measure of volume in 3-dimensional space.There can be no conversion from one to the other.
Foot and feet are the singular and plural version of the same noun. So it would be 1 foot but six feet etc.
Difference means to subtract. 'What is the difference between a person 6 feet tall and a person 5 feet tall.' There is a 1 foot difference. (6 - 5 = 1). Normally the difference is expressed as a positive number, so you would take the larger number and subtract the smaller number.
foot is singular and so suggests 1 foot whereas feet is plural suggesting 2 or more feet. Though having said that, foot is often used when feet would be properly correct, eg "I am 6 foot 1 tall" should really be "I am 6 feet 1 inch tall".
A linear foot is 12 times greater than one linear inch.
Lineal foot can be measured on the ground. It is related to an actual measurement. Linear foot is a distance not necessarily measured along the ground. Also linear foot can refer to board feet.