Question

Find the circumference of a circle whose diameter is
(i) 14 cm
(ii) 35 cm
(iii) 10.5 m

Answer 1

(i)
Circumference=2πr
$=\pi \left(2r\right)$
=π× Diameter of the circle (d) (Since, Diameter=2×radius)
⇒Circumference=Diameter×π
Diameter of the given circle is 14 cm. Circumference of the given circle=14×π
$=14\times \frac{22}{7}$
$=44cm$
Therefore, Circumference of the given circle is 44 cm.

(ii)
Circumference=2πr=π(2r)
=π×Diameter of the circle(d) As (Diameter=2×Radius)
⇒Circumference=Diameter×π
Diameter of the given circle is 35 cm. ⇒Circumference of the given circle=35×π
$\Rightarrow 35\times \frac{22}{7}=110cm$
Therefore, circumference of the given circle is 110 cm.
(iii)
Circumference=2πr =π(2r)
=π×Diameter of the circle(d) as (Diameter=2×Radius)
⇒Circumference=Diameter×π
Diameter of the given circle is 10.5 m. Circumference of the given circle=10.5×π
⇒$10.5\times \frac{22}{7}$=33 m
Circumference of the given circle is 33 m.