PLEASE help me understand this RtR experiment!

[lmercon]

Ok, I'm feeling pretty dense right now, but I can't figure out how to perform this experiment. We are in unit 28 of Res. to Rev. We are studying Issac Newton and working on an experiment that involves rolling a ball down a tube and seeing the change in the path. This is a demonstration of how the earth's gravity affects the path of the moon. The demo. has you laying a paper tube on the edge of a cookie sheet and resting the other end on the flat part. Then you tape the tube on the edge. It's supposed to form a right angle with the edge of the cookie sheet. That's where I'm totally stumped! How can it rest on the edge with the other end on the flat part and form a RIGHT angle?

HELP!

[lmercon]

Nevermind! The ole' mind finally wrapped around the concept!

[annaz]

Inquiring minds want to know how you'd get a right angle?

[lmercon]

I realized that the right angle is not to the end of the tray where it is taped but to the side that should be parallel with the tube.

[annaz]

Ah ha!