# Finding x & y position

• Sep 19th 2011, 05:15 PM
castles
Finding x & y position
I'm working on a little html5 canvas experiment and I think my question is best described in an image (not to scale)...

Attachment 22324

I'm fairly certain I need to use trigonometry to solve this.. but I'm I'm not sure how. Please help.
http://www.mathhelpforum.com/math-he...isc/pencil.png
• Sep 19th 2011, 05:36 PM
skeeter
Re: Finding x & y position
lower left coordinates should be $\displaystyle (-20,-200)$

angle between the segment A and the y-axis ...

$\displaystyle \theta = \arctan\left(\frac{1}{10}\right)$

angle between the segment in quad I and the x-axis = $\displaystyle 120 - \left[90 + \theta \right] = 30 - \theta$

$\displaystyle |A| = \sqrt{20^2 + 200^2}$

$\displaystyle x = |A|\cdot \cos(30-\theta)$

$\displaystyle y = |A| \cdot \sin(30 - \theta)$
• Sep 19th 2011, 05:49 PM
castles
Re: Finding x & y position
wow, thanks skeeter. I think I've got my head around that. I'll have a play and let you know.