What is the relationship between the arc length and the radius of a circle when the central angle is defined in radians

Need on this one asap im almost done with this subject

12 out of 30 people chose their favourite colour as blue caculate the angle you would use for blue on a pie chart

Question 6(multiple choice worth 5 points) (05.02 lc) what is the value of x? a right angle is shown divided into two parts. the measure of one part of the right angle is 10 degrees. the measure of the other part is 2x 20 40 45 85