What is the width of a wall seen from an opposing mirror?

[Aneadra]

Homework Statement

In a church choir loft, two parallel walls are
4.98 m apart. The singers stand against the
north wall. The organist faces the south wall,
sitting 0.967 m away from it. So that she can
see the choir, a flat mirror 0.855 m wide is
mounted in the south wall, straight in front of
the organist.
What width of the north wall can she see?
Answer in units of m.

Homework Equations

I'm not exactly sure, but I think snells law is incorporated somehow.

The Attempt at a Solution

I drew a diagram showing how the rays would bounce off the north wall into the southwall and I do see where some triangles are formed, other than that I'm kinda lost...

 

[Carid]

Why not trace some rays from the head of the organist to the edges of the mirror and across to the opposite wall?

 

[Redbelly98]

I'm not exactly sure, but I think snells law is incorporated somehow.

Mmmm, not quite. How about the Law of Reflection?