The circumference of a circle is proportional to the radius (a) Write down the formula for the circumference of - Maths - Ratio and Proportion

Question

​​​The circumference of a circle is proportional
to the radius
(a) Write down the formula for the circumference of a circle and
state the value
of the constant of proportionality
(b) It is also possible to state that the circumference of a circle
is proportional to
the diameter What would be the constant of proportionality in this
case?

Shruti Tyagi · Accepted Answer

Dear student,

Given: Circumference is proportional to radius⇒C=kr     
[where k is proportionality constant]               
(1)a) We know,Circumference of circle, C=2πr               
(2)Comparing (1) and (2)we get, k=2πb) We know diameter, d=2rthen, C=2πrC=π×2rC=πdYes, it is possible to state that the circumference of a circle is proportional to the diameter
And the constant of proportionality in this case is π
Regards