Question

question 5 of 10 how many degrees has △abc been rotated counterclockwise about the origin? a. 180° b. 270° c. 360° d. 90°

Explanation:

Step1: Observe rotation rule

When rotating a point $(x,y)$ counter - clockwise about the origin by $90^{\circ}$, the new coordinates are $(-y,x)$.

Step2: Check the transformation

For example, if we consider a point on $\triangle ABC$ and its corresponding point on $\triangle A'B'C'$, we can see that the transformation follows the $90^{\circ}$ counter - clockwise rotation rule.

Answer:

D. $90^{\circ}$