Question

A square has vertices T(1,2), U(4,2), V(4,5), W(1,5). If the square is rotated clockwise 90 degrees around (0,0), what are the coordinates of W?

Answer 1

(5,-1) The key to this problem is ignoring all the information that you don't need. You really don't care about the coordinates for T, U, or V. Just W is all that matters. So make a graph, label the X and Y axis, and put a point at (1,5). Now simply turn the entire paper clockwise 90 degrees. If you do this, you'll see that what was the X axis is now the Y axis. And what was the Y axis is now the X axis. Label the axis again, and read the location of the point you marked. If you do so, you'll see that you have to go 5 spaces along the X axis, hence the 5. And you'll go 1 space down on the Y axis, hence the -1. So the coordinates of W(1,5) rotated 90 degrees clockwise around (0,0) changes to (5,-1).