How to project a circle onto an angled plane?
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I have cut a hole in my ceiling to fit an 8 inch diameter circular duct perpendicular to my floor so it goes straight up. The ceiling is pitched at 15 degrees. I want to draw the shape that this hole made in my ceiling so I can cut something to go around it. How can I do this?
circle conic-sections
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add a comment |
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I have cut a hole in my ceiling to fit an 8 inch diameter circular duct perpendicular to my floor so it goes straight up. The ceiling is pitched at 15 degrees. I want to draw the shape that this hole made in my ceiling so I can cut something to go around it. How can I do this?
circle conic-sections
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it's going to be an ellipse, minor axis will be equal to diameter of the duct, major axis will be diameter of the duct divided by $cos 15°$
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– Vasya
Dec 14 '18 at 16:22
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ok, so I have an ellipse with a major axis of 10.53 and a minor axis of 8. Is there some tool that I can use to print out this shape?
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– Aaron Paul
Dec 14 '18 at 16:47
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GeoGebra, easy and free (www.geogebra.org).
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– Aretino
Dec 14 '18 at 16:50
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en.wikipedia.org/wiki/Ellipse#Drawing_ellipses. The pins-and-string method will be easiest for your application. Your major axis length looks wrong, though. The cosine of 15° is pretty close to 1 but the ratio you’ve got is about 3/4.
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– amd
Dec 14 '18 at 20:00
add a comment |
$begingroup$
I have cut a hole in my ceiling to fit an 8 inch diameter circular duct perpendicular to my floor so it goes straight up. The ceiling is pitched at 15 degrees. I want to draw the shape that this hole made in my ceiling so I can cut something to go around it. How can I do this?
circle conic-sections
$endgroup$
I have cut a hole in my ceiling to fit an 8 inch diameter circular duct perpendicular to my floor so it goes straight up. The ceiling is pitched at 15 degrees. I want to draw the shape that this hole made in my ceiling so I can cut something to go around it. How can I do this?
circle conic-sections
circle conic-sections
asked Dec 14 '18 at 16:17
Aaron PaulAaron Paul
11
11
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it's going to be an ellipse, minor axis will be equal to diameter of the duct, major axis will be diameter of the duct divided by $cos 15°$
$endgroup$
– Vasya
Dec 14 '18 at 16:22
$begingroup$
ok, so I have an ellipse with a major axis of 10.53 and a minor axis of 8. Is there some tool that I can use to print out this shape?
$endgroup$
– Aaron Paul
Dec 14 '18 at 16:47
$begingroup$
GeoGebra, easy and free (www.geogebra.org).
$endgroup$
– Aretino
Dec 14 '18 at 16:50
$begingroup$
en.wikipedia.org/wiki/Ellipse#Drawing_ellipses. The pins-and-string method will be easiest for your application. Your major axis length looks wrong, though. The cosine of 15° is pretty close to 1 but the ratio you’ve got is about 3/4.
$endgroup$
– amd
Dec 14 '18 at 20:00
add a comment |
$begingroup$
it's going to be an ellipse, minor axis will be equal to diameter of the duct, major axis will be diameter of the duct divided by $cos 15°$
$endgroup$
– Vasya
Dec 14 '18 at 16:22
$begingroup$
ok, so I have an ellipse with a major axis of 10.53 and a minor axis of 8. Is there some tool that I can use to print out this shape?
$endgroup$
– Aaron Paul
Dec 14 '18 at 16:47
$begingroup$
GeoGebra, easy and free (www.geogebra.org).
$endgroup$
– Aretino
Dec 14 '18 at 16:50
$begingroup$
en.wikipedia.org/wiki/Ellipse#Drawing_ellipses. The pins-and-string method will be easiest for your application. Your major axis length looks wrong, though. The cosine of 15° is pretty close to 1 but the ratio you’ve got is about 3/4.
$endgroup$
– amd
Dec 14 '18 at 20:00
$begingroup$
it's going to be an ellipse, minor axis will be equal to diameter of the duct, major axis will be diameter of the duct divided by $cos 15°$
$endgroup$
– Vasya
Dec 14 '18 at 16:22
$begingroup$
it's going to be an ellipse, minor axis will be equal to diameter of the duct, major axis will be diameter of the duct divided by $cos 15°$
$endgroup$
– Vasya
Dec 14 '18 at 16:22
$begingroup$
ok, so I have an ellipse with a major axis of 10.53 and a minor axis of 8. Is there some tool that I can use to print out this shape?
$endgroup$
– Aaron Paul
Dec 14 '18 at 16:47
$begingroup$
ok, so I have an ellipse with a major axis of 10.53 and a minor axis of 8. Is there some tool that I can use to print out this shape?
$endgroup$
– Aaron Paul
Dec 14 '18 at 16:47
$begingroup$
GeoGebra, easy and free (www.geogebra.org).
$endgroup$
– Aretino
Dec 14 '18 at 16:50
$begingroup$
GeoGebra, easy and free (www.geogebra.org).
$endgroup$
– Aretino
Dec 14 '18 at 16:50
$begingroup$
en.wikipedia.org/wiki/Ellipse#Drawing_ellipses. The pins-and-string method will be easiest for your application. Your major axis length looks wrong, though. The cosine of 15° is pretty close to 1 but the ratio you’ve got is about 3/4.
$endgroup$
– amd
Dec 14 '18 at 20:00
$begingroup$
en.wikipedia.org/wiki/Ellipse#Drawing_ellipses. The pins-and-string method will be easiest for your application. Your major axis length looks wrong, though. The cosine of 15° is pretty close to 1 but the ratio you’ve got is about 3/4.
$endgroup$
– amd
Dec 14 '18 at 20:00
add a comment |
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$begingroup$
it's going to be an ellipse, minor axis will be equal to diameter of the duct, major axis will be diameter of the duct divided by $cos 15°$
$endgroup$
– Vasya
Dec 14 '18 at 16:22
$begingroup$
ok, so I have an ellipse with a major axis of 10.53 and a minor axis of 8. Is there some tool that I can use to print out this shape?
$endgroup$
– Aaron Paul
Dec 14 '18 at 16:47
$begingroup$
GeoGebra, easy and free (www.geogebra.org).
$endgroup$
– Aretino
Dec 14 '18 at 16:50
$begingroup$
en.wikipedia.org/wiki/Ellipse#Drawing_ellipses. The pins-and-string method will be easiest for your application. Your major axis length looks wrong, though. The cosine of 15° is pretty close to 1 but the ratio you’ve got is about 3/4.
$endgroup$
– amd
Dec 14 '18 at 20:00