Identify the coordinates of (3, - 9) after a rotation of 180° about the origin.

Answer: (-3,9)

When we rotate 180 degrees about the origin, the rule is (x, y) - - > (-x,-y). The coordinate signs have swapped. If x is negative, then x turns positive, or vice versa. The same applies for y as well.

x = 3 becomes - x = - 3

y = - 9 becomes - y = - (-9) = 9