Question

The radius of a circle is 15. Using π, which equation expresses the ratio of the circumference to the diameter of a circle? Question 2 options: C30=π C=15πr C15=π C=r30π

Answer 1

Answer:

$C =30\pi$

Step-by-step explanation:

The circumference $C$ of the the circle with radius $r$ is  

$C=2\pi r$,

and the diameter $d$ is 2 times the radius:  

$d=2r$.

Therefore, the ratio of the circumference to the diameter is

$\dfrac{C}{d} =\dfrac{2\pi r }{2r}$

$\dfrac{C}{d} =\pi.$

And since the diameter of our circle is

$d= 2r= 2*15 =30$,

the ratio of the circumference to he diameter we get is

$\dfrac{C}{30} =\pi.$

which can be rewritten as

$\boxed{C =30\pi. }$

Answer 2

Answer:

The ratio of the circumference to the diameter of a circle is equal to $\pi$

Step-by-step explanation:

we know that

The circumference of a circle is equal to

$C=\pi D$

we have

$D=2r=2(15)=30\ units$ ----> the diameter is two times the radius

so

$C=30\pi\ units$

The ratio of the circumference to the diameter of a circle is equal to

$ratio=\frac{30\pi}{30}$

simplify

$ratio=\pi$