Coordinate (1,-2), angle of intersection thru origin?

AI Thread Summary
To find the angle of intersection from the point (1,-2) to the origin, a triangle can be set up along the axes. The angle can be calculated using basic trigonometry, specifically by determining the slope of the line connecting the point to the origin. The user initially struggled with this simple geometry problem but ultimately resolved it by recalling the method of using right triangles. The discussion highlights the importance of visualizing geometric relationships in solving physics problems. The user expressed satisfaction in finding the solution independently.
bchandler
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I'm trying to do a simple electric field due to point charges problem, but I'm stuck on a very simple detail. There are a number of point charges on an xy plane, and one of the point charges is at the cooridinate (1,-2). I need to figure out which angle a line drawn from this point to the origin would make with the x-axis to do the problem, but can't figure it out! I'm sure as soon as someone tells me the answer I'll remember how to find it; it's just a simple geometry problem!

Can anyone help? I can do the rest of the problem, its just this one snag that has me held up.
 
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Nevermind, I figured it out. I just set up a triangle along the axes to figure out the angle and the distance. Should have thought about this one more... Feel free to delete mods...
 
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