Question

triangle $\triangle abc$ is the image of $\triangle abc$ under a rotation about point $q$.
determine the angle of rotation.
choose 1 answer:
a $-165^{\circ}$
b $-120^{\circ}$
c $120^{\circ}$
d $165^{\circ}$

Explanation:

Step1: Connect corresponding points to Q

Connect $A$ to $Q$, $A'$ to $Q$; $B$ to $Q$, $B'$ to $Q$.

Step2: Identify rotation direction & measure angle

Negative angles indicate clockwise rotation. Measure the clockwise angle between $QA$ and $QA'$ (or $QB$ and $QB'$). The angle matches $-120^\circ$.

Answer:

B. $-120^\circ$