Diameter of the circle = 40 cm
Radius (r) of the circle = 40/2 cm = 20cm
Let AB be a chord (length = 20 cm) of the circle.
In ΔOAB, OA = OB = Radius of circle = 20 cm
Also, AB = 20 cm
Thus, ΔOAB is an equilateral triangle.
θ = 60° = π/3 radian
We know that in a circle of radius r unit, if an arc of length l unit subtends
an angle θ
Thus, the length of the minor arc of the chord is 20π/3 cm