Question

how does the resistance of the conductor depends upon its radius.

Answer 1

Resistance of conducter depends on its cross sectional area which isdependant on radius. ... Resistance isthe property which opposes the flow of electric current. The resistance of anyconductor is directly proportional to the length of conductor and isinversely to its area of cross section.
Hope it's help you

Answer 2

$r = rho \times \frac{length}{area}$
resistance is inversely proportional to the cross sectional area of wire...whereas area of cross section =πr^2

so by this

Resistance is inversely proportional to r^2