help on determining angle plz!
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Forum Name: General Discussion
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URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=17605
Printed Date: July 14, 2025 at 2:12 PM
Topic: help on determining angle plz!
Posted By: jayzeey
Subject: help on determining angle plz!
Date Posted: August 14, 2003 at 8:22 PM
I am building a wedge sub enclosure that is to fit behind my bench seat in my 1983 Chevy Scottsdale pickup. How do I figure the angle for the slanted front piece of the box? I know it involves cosine, but I can't remember the formula. I've gone as far as asking geometry teachers, searching in books and even college notes, and I can't believe I can't find this. If you need more info, let me know. Anyhelp would be great. Thanks a lot. Jake
Replies:
Posted By: Okinawa_Novice
Date Posted: August 14, 2003 at 9:45 PM
Jake, Hi, I'm waay out of school and not the brightest bulb in the trashcan, but I think I remember a thing or two about basic geometry. I wish there was a doodle pad on this forum to assist us. Your question is about figuring out the angle of the front piece of a wedge shaped box. Now, do you know any of the other dimentions or angles? And when you say a wedge, do you mean a basic triangle or a kind of rectangle with a triangle attached to it (like a 4 or 5 sided shape?) If your box is square for the most part, just break the pattern up into the rectangles and triangle that make it up and remember that a triangles 3 angles add up to 180 deg. I might be thinking way too basic here but as I said before, I'm oldschool. I hope this helped a little, if not, hey, I tried. ------------- I can do anything... just not on the first try...
Posted By: mj239air
Date Posted: August 14, 2003 at 9:52 PM
just get an adjustable protractor, i have one that is aluminum and has a long piece that you can adjust to whatever angle you need. place a piece of wood on the floor, then adjust the protractor to the angle of the seat. better yet, just measure the bottom distance from the back of the trcuk cab, measure the top, put a piece of mdf across the 2 and there's your angle. you can measure it outside the vehicle and then cut away.
Posted By: aggie altima
Date Posted: August 15, 2003 at 4:35 PM
if you have a scientific calculator, do this. first divide the height of the box by the length of the front piece. (that is height/front_piece). now that you found that, use it with the inverse sine button, which is labeled sin^-1.
if you have a graphing calculator, enter:
sin^-1(height/front_piece)
for example, if the height is 15, and the front piece is 20, you should get an angle of 48.59
this equation should give you the angle of the front piece. this was derived using the formula for sine, which is sine(angle)=opposite/hypotenuse, so to find the angle you would bring the sine to the other side of the '=' sign, thus giving you angle=inverse_sine(opposite/hypotenuse).
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Jon
Don't like rockford subs? Then don't look at my car =)
Posted By: xetmes
Date Posted: August 15, 2003 at 5:30 PM
Basic trigonometry can be a life saver sometimes.
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