Subject: 2-D Graphing

I have the following information Given.

(X1, Y1) Origional Point
(X2, Y2) Origional Point After a Rotation
(Xa, Xb) Center of Rotation

What formula would I use to figure out the angle the point was rotated?

Hi Jay,
We suggest a vector approach to this problem. If v1 and v2 are the two vectors in the diagram then
where is the angle between them. Since the two vectors have the same length, is the angle whose cosine is
Chris and Harley
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