To determine the radius of the circle using the portion shown in the picture you have to use the formula to calculate the arc length of the segment.
Where
s is the arc length
r is the radius
π is the number pi
θ is the central angle
For the portion of the circle shown in the picture, the arc length is s=15cm and the angle is θ=27º
The first step you have to write the formula in terms of r:
-Divide both sides by 2π
-Multiply both sides of the expression by the reciprocal fraction of (θ/360), which is (360/θ)
Next, replace the formula with the given arc length and angle and calculate the radius:
The radius has a measure of 31.8cm