Question

In a circle, the circumference and diameter vary directly. Which of the following equations would allow you to find the diameter of a circle with a circumference of 154 if you know that in a second circle the diameter is 14 when the circumference is 44?

Answer 1

d=kC
Plug in what we know and solve for k:
14=k(44)
k=14/44

so
d=(14/44)(154)
x=49

Answer 2

`d=(7)/(22)* 154=49`

Explanation:

Let circumference be C and diameter be d.

In a circle, the circumference and diameter vary directly that is

C = kd

You know that in a second circle the diameter is 14 when the circumference is 44.

C = kd

44 = k x 14

`k=(44)/(14)=(22)/(7)`

Circumference of unknown diameter circle = 154

`154=(22)/(7)d\\\\d=(7)/(22)* 154 = 49`