Question

Answer the following :

In a circle of diameter 40 cm, the length of a chord is 20 cm. Find the length of minor arc of the chord.

Answer 1

Let ‘O’ be the centre of the circle and AB be the chord of the circle.

Here, d = 40 cm

∴ r = `40/2` = 20cm

Since OA = OB = AB,

ΔOAB is an equilateral triangle.

∴ The angle subtended at the centre by the minor

arc AOB is θ = 60° = `(60 xx pi/180)^"c"`

= `(pi/3)^"c"`

∴ `l` (minor arc of chord AB) = rθ

= `2θ xx pi/3`

= `(20pi)/3"cm"`.