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Help!! How do I find an angle?

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Forum topic by shelly_b posted 06-24-2013 04:59 PM 1557 views 1 time favorited 55 replies Add to Favorites Watch
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shelly_b

848 posts in 865 days


06-24-2013 04:59 PM

I got a job making a kitchen island for a woman. The thing is, she needs the base by 7/2 b/c that’s when the counter top is coming in and they said the base has to be done. The problem I am having is finding the angles. And I also need to know what the length of the centers will be. I worked all night on sketchup for the first time and it ended up being a big waste of time. My other option is to go lay it out in a full size model in the garage. I guess I have been out of school too long. I forget what I learned in cal and pre-cal. Thanks!


55 replies so far

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Monte Pittman

15450 posts in 1085 days


#1 posted 06-24-2013 05:03 PM

Do I understand correctly that it’s a trapezoid?

-- Mother Nature created it, I just assemble it.

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Monte Pittman

15450 posts in 1085 days


#2 posted 06-24-2013 05:06 PM

If I understand it correctly the center distance is 48.836 inches

-- Mother Nature created it, I just assemble it.

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shelly_b

848 posts in 865 days


#3 posted 06-24-2013 05:08 PM

Yes it is…but I was thinking the vertical center would be less than 48. And I’m not sure I have the horizontal center right either, that was just my guess.

View JustJoe's profile

JustJoe

1554 posts in 785 days


#4 posted 06-24-2013 05:08 PM

http://www.1728.org/quadtrap.htm

-- This Ad Space For Sale! Your Ad Here! Reach a targeted audience! Affordable Rates, easy financing! Contact an ad represenative today at JustJoe's Advertising Consortium.

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Monte Pittman

15450 posts in 1085 days


#5 posted 06-24-2013 05:09 PM

Figured it wrong, 47.149 inches

-- Mother Nature created it, I just assemble it.

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Monte Pittman

15450 posts in 1085 days


#6 posted 06-24-2013 05:11 PM

Your horizontal center I believe is correct. This is a lot of thinking for Monday. :-)

-- Mother Nature created it, I just assemble it.

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shelly_b

848 posts in 865 days


#7 posted 06-24-2013 05:17 PM

lol thanks Monte:) That sounds right.

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shelly_b

848 posts in 865 days


#8 posted 06-24-2013 05:22 PM

That is awesome Joe! Thanks alot:) That gave me all the answers I need:) I was expecting to get a tutorial on how to find them, not an awesome calculator that did it all for me lol.

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shelly_b

848 posts in 865 days


#9 posted 06-24-2013 05:22 PM

According to the calculator, you are right monte:)

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DS

2132 posts in 1168 days


#10 posted 06-24-2013 05:26 PM

If you draw a perpendicular line from the 62” edge over to the 80” edge you get a right triangle with the a = 9”, b = unknown and c = 48” (Assuming equal angles on left and right sides)

Using the pathagorean theorim, a^2 + b^2 = c^2, your values are as below;

9^2 + b^2 = 48^2

solving for b gives you the dimension you are looking for.

b = SQR (48^2 – 9^2)

simplified to;

b = SQR ( 2304 – 81)

b = 47.1487”

Just as Monte said. (My teacher always said to show your work)

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

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DS

2132 posts in 1168 days


#11 posted 06-24-2013 05:33 PM

For the angle, take the ratio of the lengths (47.1487 / 9) and do an inverse tangent function on it.
That gives you the first angle of 79.19 degrees.
Subtracting from 180 degrees, gives you the other angle of 10.81 degrees. (180 – 90 – 79.19 = 10.81)

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

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DS

2132 posts in 1168 days


#12 posted 06-24-2013 05:40 PM

And that concludes the “Math Monday” tutorial. (You did say you were expecting one)

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

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shelly_b

848 posts in 865 days


#13 posted 06-24-2013 05:43 PM

lol thanks guys:) It will be nice to know how to do it with pencil and paper for the next time:)

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oldnovice

3868 posts in 2115 days


#14 posted 06-24-2013 05:44 PM

Doug, you must have had the same teachers as I did!

Don’t you just love plane geometry? It was one of my favorite subjects in school and now that I have been out for a “few” years.

-- "I never met a board I didn't like!"

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DS

2132 posts in 1168 days


#15 posted 06-24-2013 05:46 PM

Hehe, four years of Algebra were NOT wasted on me! (I laugh at those who said, “When will I EVER use this stuff”)

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

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