Question

1. using the triangle, what are the new coordinates if triangle abc is rotated 180° counterclockwise about the origin?

a. a(7, -7), b(7, -4), c(-2, -4)
b. a(7, -7), b(4, -7), c(2, -4)
c. a(7, 7), b(7, -4), c(-2, 4)
d. a(-7, 7), b(4, 7), c(-4, -2)

Explanation:

Step1: Recall rotation rule

When a point $(x,y)$ is rotated 180° counter - clockwise about the origin, the new coordinates are $(-x,-y)$.

Step2: Find new coordinates of point A

The coordinates of point A are $(7, - 7)$. After a 180° counter - clockwise rotation about the origin, the new coordinates of A are $(-7,7)$.

Step3: Find new coordinates of point B

The coordinates of point B are $(7,-4)$. After a 180° counter - clockwise rotation about the origin, the new coordinates of B are $(-7,4)$.

Step4: Find new coordinates of point C

The coordinates of point C are $(-2,-4)$. After a 180° counter - clockwise rotation about the origin, the new coordinates of C are $(2,4)$.

Answer:

d. A(-7,7), B(4,7), C(-4,-2)