If DM = 45, what is the value of r?

Answer 1

If DM is the diameter, and r is the radius, then r= DM / 2

So r = 22.5.

The radius of a circle is the straight line distance from the center of the circle to its outdide boundary (the circumference). When we say circumference, we may also be referring to its distance, that is, the distance around a given circle.

The diameter of a circle is the straight-line distance from one side of a circle to the other side, and passing through the circle's center.

You should also always include the units of measurement: feet, meters, etc.