The resistance of a conductor is given by:

where

is the resistivity of the material
L is the length of the conductor
A is its cross-sectional area
We can use this formula to solve both parts of the problem.
a) The length of the copper wire is L=1.0 m. Its diameter is d=0.50 mm, so its radius is

And its cross-sectional area is

The copper resistivity is

, therefore the resistance of this piece of wire is

b) The length of this piece of iron is L=10 cm=0.10 m. Its cross-sectional size is L=1.0 mm=0.001 m, so its cross-sectional area is

The iron resistivity is

, therefore the resistance of this piece of wire is