Extremely Hard Physic Question (Ray diagram)

[Nope]

Homework Statement

http://img163.imageshack.us/img163/7010/78614537.jpg
o= student
The position of the teacher is (d) from the mirror.
mirror is 6m
a) Calculate the maximum distance(d) of the corridor from the mirror
b) Trace the diagram. Draw the ray diagram to support your calculation in a)

This question was on the my unit test. But i have no idea of how to find the distance. I am very curious of how to do it, if anyone can help me out..
Thanks :)

Homework Equations

The Attempt at a Solution

 

[rl.bhat]

Ray from the student will clear the edge of the corridor if it hits the mirror at a distance 1.5 m from the bottom. Find the angle made by the ray to the mirror and remaining length of the mirror. From that you can find the maximum distance d.

 

[Nope]

http://img137.imageshack.us/img137/6963/37641899.jpg ??[/URL]
I still don't get how to find d..

 

[rl.bhat]

Continue the reflected light past the edge. It hits the wall a a distance d. Then d/4.5 = tanθ. Now what is tanθ?

 

[Nope]

I am confused...
Where is the 4.5?
http://img341.imageshack.us/img341/8523/98303310.jpg??

 

[rl.bhat]

Length of the mirror 6 m - 1.5m = 4.5 m

 

[Nope]

Oh...!
But How is that equal to d?
Or is that the maximum distance that he can see the teacher?

 

[rl.bhat]

From the first part, find tanθ = 3/1.5
In the second part tanθ = d/4.5. Find d.

 

[Nope]

Yes, i understand.
But "d" seem to much shorter than the actual diagram...