Question

Point D(-3, 5) is a vertex triangle of d e f. After a rotation of the triangle about the origin, D is located (3,-5). Which of the following was the rotation of the triangle?
A. 90-degree clockwise
B. 90° counterclockwise
C. 180 degrees
D. 360 degrees

Answer 1

Answer- 180 degree rotation.

Basically how I remember it is by 90 degree clockwise is switch x,y and change the sign of the x—> y,-x. 90 degree counterclockwise is switch x,y and change the sign of the y —> -y, x. 180 degree is changing both signs with no switch. 360 stays the same.