How is the resistance of a wire affected if it’s (a) length is doubled, (b) radius is doubled?

(a) If the length is doubled, the resistance of the wire doubles as resistance of a wire is directly proportional to the length of the wire.

(b) The resistance of a wire becomes less or one-fourth when the radius of the wire is doubled as resistance of a wire is inversely proportional to the area of cross section of the wire.