That depends what it is the length of.
If you multiply two lengths in feet, you get square feet, not cubic feet.
5.15 feets
three feets
44 lots of 18 feet lengths is a length of 792 feet
1 yard are 3 feets
10x10=100 ft
157 centimeters is 5.15 feet.
50 feet (not feets) equal 15.24 metres (not maters).
3
186 centimetres make 6.102 feet. (1 foot, many feet: feets has no meaning)
2186 square feets = how many 10 x10 booths
none