Step-by-step explanation:
Given, the central angle of the arc = [tex]\frac{2\pi }{5}[/tex] = 1.256
Length of the arc = 20 cm
Radius of the circle = ?
Radius of the circle = [tex]\frac{arc length}{central angle}[/tex] = [tex]\frac{20}{1.256}[/tex] = 15.92 cm