12. On your own graph paper, sketch a graph to rotate ΔABC 90∘
counterclockwise about point
B
.

13. On your own graph paper, sketch a graph to rotate
ΔABC 90∘
counterclockwise about point
A
.

14. On your own graph paper, sketch a graph to rotate
ΔABC 90∘
counterclockwise about point
C
.

15. Could you have used the rule that a
90∘
counterclockwise rotation takes
(x, y)
to
(−y, x)
to perform the previous three rotations? Explain.