How Can I Calculate the Displacement and Path Length of a Fly in a 3D Room?

[maxalador]

This is my summer homework and my teacher gave us some new stuff to learn.

Homework Statement

1. A room has dimensions 3.00 m x 3.70 m x 4.30 m. A fly starting at one corner flies around, ending up at the diagonally opposite corner.
a) What is the magnitude of its displacement?
b) Could the length of the path be less than this magnitude? Greater? Equal?
c) Express the components of the displacement vector in unit vector notation.
d) If the fly walks along the walls (not necessarily along the edges), what is the length of the shortest possible path? Hint: It will help if you unfold the walls of the “box” and flatten them into a 2D plane

Homework Equations

(i-j-k)

The Attempt at a Solution

I know that i have to put it into (3i-3.7j-4.3k), but I don't know what I have to do next

 

[barryj]

for a) Think of Pythagorean theorem in three dimension.

 

[maxalador]

thanks a ton