Consider her starting position to be origin(0,0,0)
she travels 60 km east and then 8 km north
if east is taken as positive x axis and north as positive y axis, then her position can be represented by the vector (60î+8k)
thus her distance from initial position i.e. Origin, is given by the amplitude of vector which is root(60sq+8sq) = root(3600+64) = root(3664) =4*root(229) metres
