Question

Find the radius of the circle if an arc of length 4 ft on the circle subtends a central angle of 45°. (round your answer to two decimal places.)

Answer 1

If the 4 foot section of the circle is created by a central angle of 45 degrees, then the circumference is 8 times larger or 32 feet.
Circumference   =   2 • π • radius
radius = circumference / 2*PI
radius = 32 / 2*3.14159
radius = 5.0929581789
radius = 5.09 (rounded)