A twisted line which may be approximated by a two-wire line is very useful in the telephone

Question:

A twisted line which may be approximated by a two-wire line is very useful in the telephone industry. Consider a line comprised of two copper wires of diameter 0.12 cm that have a 0.32-cm center-to-center spacing. If the wires are separated by a dielectric material with ε = 3.5εo, find L, C, and Zo.