how do you work out a radius and diameter don't know at all there is a circle with the number 5mm and they want me to tell them what the radius is and the diameter

Answer 1

What does the 5mm represent?

Is it the circumference?

Answer 2

The common distance of the points of a circle from its centre is called its radius.

Diametar=2*Radius

go to en.wikipedia and type circle in search field.

Answer 3

5×3.14 =d
D÷2=r