The new coordinates are (-1, -2), (-1,-6) and (-5,-4). Rotating a triangle clockwise 270 degrees about the origin is the same thing as rotating a triangle 90 degress counterclockwise. Here is my work:
1: Original Coordinates: (-2,1), (-6,1), (-4,5)
2: y value signs turn negative: (-2,-1), (-6,-1), (-4,-5)
3: Switch x and y values: (-1,-2), (-1,-6), (-5,-4)