Question

What’s the diameter of the circle of the circumference is 30 pi inches

Answer 1

30?
30pi = 2pi r
30pi / 2pi = 15
15 = r
double the radius to get the diameter
15)2 =30

Answer 2

Answer:

Step-by-step explanation:

The circumference formula for a circle is

$C=2\pi r$ or $C=\pi d$

We'll use the second one since our problem wants us to find diameter.  If we know that the circumference is 30π, then we will sub in 30π for C and solve for d:

30π = πd so

30π/π = d

The π's cancel out, leaving us with a diameter of 30 inches.