Learning Objectives
- Convert inches into fractions of a foot.
- Convert feet and inches into feet only.
First, let’s look at notation.
Notation
One foot is equivalent to 12 inches. There are different ways to indicate feet (plural for foot) and inches.
Equivalent Notation
| foot | ft. | ft | ‘ |
| inch | in. | in | “ |
Example: 1 foot 2 inches = 1 ft. 2 in. = 1 ft 2 in = 1’ 2”
A common misconception when using inches and feet, is to assume that 12 feet 6 inches is equal to 12.6 feet. It is not!
So, what is it?
Let’s look at a ruler. Notice that 6 inches is half the length of the ruler. Therefore, 6 inches = 1/2 foot.
To determine the fraction of a foot, divide the inches by 12. Three inches divided by 12 is 0.25 feet. Nine inches divided by 12 is 0.75 feet.
Examples
Example 1: Convert 31 feet 6 inches to feet only.
Answer: 31 feet 6 inches = 31.5 feet
Example 2: Convert 11 ft. 3 in. to feet only.
Answer: 11 ft. 3 in. = 11.25 ft.
Example 3: Convert 64’9” to feet only.
Answer: 64’9” = 64.75’
Example 4: Convert 42’6” to feet only.
Answer: 42’6” = 42.5’
Four inches divided by 12 is 1/3 or 0.33 feet (if we round to the nearest hundredth). Eight inches divided by 12 is 2/3 or 0.67 (if we round).
Examples
Example 5: Convert 75 ft. 4 in. to feet only.
Answer: 75 ft. 4 in. = 75.33 ft.
Example 6: Convert 21’8″ to feet only.
Answer: 21’8″ = 21.67′
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