Question

the diameter of the circle is 5. find the radius

Answer 1

The radius is half of the diameter

So if the diameter was 12, then the radius would be 6 (since 12/2 = 6)

This isn't your answer since it's only an example

Answer 2

Let d= diameter
Let r= radius
\[d=2r~~~~~~~~~~~~~~~~~~or~~~~~~~~~~~~~~~~~r={d\over2}\]
so you said that \(d=5\) (the diameter is 5):\[r={5\over2}\]