OK guys, I need some help with this one. My math skills are not what they once were and I don't know who else to ask.

I have been asked to respond to a 60 ft x 40 ft barn/shed wood pole, wood frame structure with metal sheeting sides and roofing. There is a 12 ft x 12 ft opening on the west side of the structure. Approximately 10 ft. - 15 ft. inside the opening, the owner had stored items which included dried wood, glass bottles, motor oil, and other petroleum products used for the farm operation etc. According to responding firefighters they encountered heavy, intense fire in this area.

Also inside this structure are two tractors, a boat, 1989 Trans Am and a 2006 Chevy Silverado pick, which was last driven approximately 2 weeks prior to the fire.

The weather at the time of the fire was clear skies, bright sun. The fire was discovered at approximately 1:00 p.m. The position of the sun was 55 degrees in the setting mode.

I know there is a possibility of the fire having been caused by a prism effect of the sunlight shinning on the glass bottles, which I wish to eliminate/prove as being the cause of the fire. Thus, I pose the following questions.

What would the mamimum distance into the sheds opening could/would the sun's rays have been allowed to reach with a 12 ft. vertical opening and 55 degree angle of the sun?

My thoughts are if the maximum distance was shorter than the glass bottles, then this would eliminate the prism possibility. Am I wrong to think this?