Question

which rule explains why these triangles are similar?

sss
sas
aa
none of the above; the triangles cannot be proven similar

Explanation:

Step1: Identify marked angles

In $\triangle GHF$, $\angle G$ is marked; in $\triangle UTS$, $\angle T$ is marked. $\angle F$ in $\triangle GHF$ and $\angle U$ in $\triangle UTS$ are also marked as equal.

Step2: Apply similarity rule

When two pairs of corresponding angles of two triangles are equal, the AA (Angle-Angle) similarity rule confirms the triangles are similar.

Answer:

AA