the radius of a circle is 10 using pi which equation expresses the ratio of the circumference of the circle to the circle's diameter

pi

Step-by-step explanation:

The radius of the circle is 10 units

The circumference of a circle is given by the formula:

C = 2 * pi * r

The diameter of a circle is twice the radius

d = 2r

We want the ratio of the circumference to the diameter

C/d = (2*pi*r) / 2r

Canceling out the 2 and the r, we are left with pi

C/d = pi