
Rotation of a triangle
Hi,
I have a triangle with the points A( 5,2) B(0,0) and C(4,2) . I have to rotate the triangle so that the line BA sits on the positive x axis. I am stuck, how to work out the values for sin, cos and tan?
I have worked out the lengths of those lines BA = sqroot[29], AC = sqroot[17] and BC = sqroot[20]. After that I have no idea where to start, any help is appreciated.

use the sine and cosine laws to find two angles, then draw line AB on the xaxis, since you know how long it is, and then lines AC and BC off of it having calculated the right angles
a^2 = b^2 + c^2  2bcCosA
a/SinA = b/SinB = c/SinC

Thanks, I think I get it. It says though I don't need the angle but I should express the rotation as an equation. Do you know about that?