How do you find the circumference of a circle if you know a certain length?

Question

If you know that 4.5 centimeters is 38.16 degrees of the circle, how do you find the circumference and radius of that circle?

Answer 1

c = 4.5*(360/38.16) cm

r = c/2pi

Answer 2

Cross multiply and divide

4.5 X 360 = 1620

1620/38.16 = 42.45283 cm = circumference.

radius = 1/2 circumference / PI

Answer 3

Are those 4.5 cm a part of the circle or the distace between the two points where the angle length lines intersect with the circle?

If it's a part of the circle then

4.5 cm ------------ 38.16 degrees

x cm(the full length) ------- 360 degrees

x = (360 * 4.5) / 38.16 = 42.452830188679245283018867924528

The length of the circle a.k.a. the circumferrence is 2 * pi * radius or the diameter * pi.

diameter = 42.452830188679245283018867924528 / 3.1415926535897932384626433832795 = 13.513155545538283225659942173135

radius = diameter / 2 = 13.513155545538283225659942173135 / 2 =

6.756577772769141612829971086565