Well, a 12-inch ruler is equal to 1 foot, so you could use that. You could also use a tape measure.
15 feet
There is no way to convert linear feet to square feet because the unit 'linear feet' measures length but the unit 'square feet' measures area.
degrees measures angles. radians measures angles in the center of a circle. feet measures distance.
The square footage of a circle that measures 159 feet in circumference is about 2,012 square feet.
It measures 18 feet.
108 feet
720 feet
56
63
30
32.
110'