Step 1: Understand the relation for the angle of the prism.
In a prism, the total angle of the prism \( A \) is related to the angles of refraction \( r_1 \) and \( r_2 \) at the two faces of the prism. The formula to calculate the angle of the prism is:
\[
A = r_1 + r_2
\]
Where:
\( r_1 \) is the angle of refraction at the first face of the prism,
\( r_2 \) is the angle of refraction at the second face of the prism.
Step 2: Apply the formula.
Thus, the angle of the prism is the sum of the angles of refraction at both the faces of the prism.
Final Answer: The correct answer is \( r_1 + r_2 \).