Question

Is it possible to draw a circle without knowing its radius?

Answer 1

Not without knowing more about the particular circle,

Explanation:

Every circle satifies the equation: `(x-a)^2+(y-b)^2 = r^2` where r is the radius of the circle centred at point `(a,b).`

Here we are asked whether it is possible to draw a circle without knowing its radius. Considering the equation of the general circle above we would have to conclude, no.

To draw the circle we would need to know both its centre and its radius.

However, if we assume the centre to be `(0,0)` we would still need more information about the particular circle to determine its 'size' (read radius).

Such information might be the circumference or the area of the circle, from which we could deduce the radius.