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A few days ago I got really excited when I found the equation for a retangles radius (distance from its center to its perimeter given an angle)

I have no idea if this is something very simple and stupid but my math teacher said it was impressive, I'm still in high school

It's like this:

(w/2)*sqrt(cos^2(theta)) + (h/2)*sqrt(sin^2(theta))

(Or my attempt at latex):

[tex]\frac{w}{2}\sqrt{cos^{2}(\theta)} + \frac{h}{2}\sqrt{sin^{2}(\theta)}[/tex]

gives the length of the line from the center of a rectangle (width w, height h) to its perimeter at angle of theta.

I graphed it also with x = theta (radians), for a rectangle of width 1 and height 1:

http://dl.dropbox.com/u/1828729/rr/graph.png [Broken] (it's a big image)

I

I have no idea if this is something very simple and stupid but my math teacher said it was impressive, I'm still in high school

It's like this:

(w/2)*sqrt(cos^2(theta)) + (h/2)*sqrt(sin^2(theta))

(Or my attempt at latex):

[tex]\frac{w}{2}\sqrt{cos^{2}(\theta)} + \frac{h}{2}\sqrt{sin^{2}(\theta)}[/tex]

gives the length of the line from the center of a rectangle (width w, height h) to its perimeter at angle of theta.

I graphed it also with x = theta (radians), for a rectangle of width 1 and height 1:

http://dl.dropbox.com/u/1828729/rr/graph.png [Broken] (it's a big image)

I

__needed__to share this, excuse me if it's ridiculously simple.
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