Question

which angles are adjacent angles?
\\( \angle efc \\) and \\( \angle efh \\)
\\( \angle efc \\) and \\( \angle bcf \\)
\\( \angle efc \\) and \\( \angle bca \\)
\\( \angle efc \\) and \\( \angle dca \\)

Explanation:

Step1: Recall the definition of adjacent angles

Adjacent angles share a common vertex and a common side.

Step2: Analyze $\angle EFC$ and $\angle EFH$

They do not share a common side (except for a part of the ray in a non - adjacent sense as they are on a straight line but the "common side" concept for adjacent angles requires a more specific sharing).

Step3: Analyze $\angle EFC$ and $\angle BCF$

They share a common vertex \(C\) and a common side \(CF\).

Step4: Analyze $\angle EFC$ and $\angle BCA$

They do not share a common vertex or a common side.

Step5: Analyze $\angle EFC$ and $\angle DCA$

They do not share a common vertex or a common side.

Answer:

$\angle EFC$ and $\angle BCF$