In a triangle, the sum of all interior angles is always 180°. Given that one angle is 45° and the other two angles are congruent, we can let the measure of each of the congruent angles be \( x \).
The equation that represents the sum of the angles in the triangle can be written as follows:
\[ x + x + 45 = 180 \]
This simplifies to:
\[ 2x + 45 = 180 \]
Thus, the equation that could be used to determine the degree measure of one of the congruent angles is:
2x + 45 = 180