Question

select all the pairs of adjacent angles.

Explanation:

Step1: Recall the definition of adjacent angles

Adjacent angles share a common side and a common vertex, and have no overlapping interior.

Step2: Analyze each pair

• For $\angle BCA$ and $\angle DCA$: They share side $CA$ and vertex $C$, so they are adjacent.
• For $\angle EFC$ and $\angle GFC$: They share side $FC$ and vertex $F$, so they are adjacent.
• For $\angle EFH$ and $\angle GFH$: They share side $FH$ and vertex $F$, so they are adjacent.
• For $\angle BCA$ and $\angle BCF$: They share side $BC$ and vertex $C$, so they are adjacent.

Answer:

$\angle BCA$ and $\angle DCA$, $\angle EFC$ and $\angle GFC$, $\angle EFH$ and $\angle GFH$, $\angle BCA$ and $\angle BCF$