Need help calculating coordinates for a tangent point.

Aug 2017
4
0
Tulsa, OK


So let's say I know coordinates for D (-10171.62, 490.26) angle at that point is 75.52. Also, line EF is a section of a line that starts at -10249, 0 and ends at -10094.8, 7615.2. How do I find the coordinates for A?

BTW, the angle at A is 91.16
 
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skeeter

Math Team
Jul 2011
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Texas
So let's say I know coordinates for D (-10171.62, 490.26) angle at that point is 75.52. Also, line EF is a section of a line that starts at -10249, 0 and ends at -10094.8, 7615.2. How do I find the coordinates for A?

BTW, the angle at A is 91.16
Your image doesn't seem to match up with the info you provided.

line EF is a section of a line that starts at -10249, 0 and ends at -10094.8, 7615.2
If point E has coordinates (-10249, 0) and point F is (-10094.8, 7615.2), then point F's x-coordinate should be less than -10249. Note -10094.8 > -10249

BTW, the angle at A is 91.16
What angle at A? The angle at the intersection of the tangent line and radius at point A is 90 degrees.

I advise you to make a better sketch that fits your given information.
 
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Aug 2017
4
0
Tulsa, OK
Sorry, I found that image on google and thought it may be enough to show the point I'm trying to find coordinates for. I'll try to draw something that will be a little closer visually.
 
Aug 2017
4
0
Tulsa, OK
Trig_Problem.jpg

I know the drawing shows the known point on the circle looking more like it is at about 50 degrees, but I hope that is close enough.
 

skipjack

Forum Staff
Dec 2006
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Can you label all relevant points (A, D, E, F, etc.) and mark the known angles?
 

skeeter

Math Team
Jul 2011
3,196
1,724
Texas
I'm not seeing the 75.52 degree angle by point D