Question 1141254
If Debra, mirror, and bottom of tree are points on the ground all on one line, then the two right triangle are these:  LEFT: y and 33 as the legs and unknown hypotenuse.  RIGHT:  6 and 9.7 as legs and unknown hypotenuse.  The two angles at the mirror are of same measure; that is,  the 33 and the hypotenuse of LEFT triangle makes same angle measure as the 9.7 and the hypotenuse of the RIGHT triangle.


Note, these are two SIMILAR triangles.

{{{highlight_green(y/33=6/9.7)}}}


{{{highlight(y=20.4)}}}