# Find a point position on a rotated rectangle not knowing the angle

I have a similar question to this post, except that I don't know the rotation angle. I just need to put the upper left corner of the rotated rectangle to (Xmin, Ymin). How can I calculate the rotated position B from the original position A?

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I suggest to put the rectangle in the middle of the image and actually rotate around the center of the rectangle. That would make calculations a lot easier (its only $(r\cos \alpha, r\sin \alpha)$ where $r$ is the distance from the center to the corner and $\alpha$ a respective angle to a corner. – Peter Patzt Jul 2 '11 at 19:11
Oh, never thought of it. Thanks, will do! – springrolls Jul 2 '11 at 19:22