Physics
posted by Tom .
Find the distance light travels from its starting point, S to its final point, F by traveling two different paths: Reflecting from point A, and reflecting from point B.
From point S to A is 30 cm, from point A to B is 30 cm, from point B to F is 30 cm, and from the mirror to point F is 30 cm.

I am not able to visualize this from your description. Your question may go unanswered, unless someone else can figure out where the points are in one or two dimensions.

S +\ + /+F
+ \ + / +
30cm+ \ + / +30cm
+ \ + / +
+ \+/+mirror
A 30cm B 30cm
a^2 = b^2 = c^2
I don't know where to go from here 
the diagram I drew looked nothing like that.The mirror is on the bottom, and B is in the middle, and A is on the left bottom corner. S is on the upper left corner, and F is on the upper right corner. There's 30 cm between each point. There's some triangles.