posted by robert .
After a triangle is rotated 180 degrees, its vertices are at (-4,1),(-1,4), and (-5,-8). What were the coordinates of the vertices before the rotation?
I think the answer is (1,-4), (4,-1),(8,-5). In rotation, the coordinates get switched. All I just did was switch the numbers and signs. Is this right?
do you want your rotation about the origin?
If so, then the line joining a point and its image point should pass through the origin, yours don't.
if you interchange the x and y coordinates you are forming a reflection in the line y=x
try switching the signs only and plotting the points.
You should have tried plotting right away.