Let the measure of one angle be denoted as \( x \). According to the problem, the other angle is \( 4x + 15 \) degrees.
Since the two angles are complementary, their sum must equal 90 degrees:
\[ x + (4x + 15) = 90 \]
Now, simplify the equation:
\[ x + 4x + 15 = 90 \] \[ 5x + 15 = 90 \]
Next, subtract 15 from both sides:
\[ 5x = 90 - 15 \] \[ 5x = 75 \]
Now, divide by 5 to solve for \( x \):
\[ x = \frac{75}{5} = 15 \]
Now that we have the value of \( x \), we can find the measure of the other angle:
\[ 4x + 15 = 4(15) + 15 = 60 + 15 = 75 \]
Thus, the two complementary angles are:
\[ \text{First angle: } 15 \text{ degrees} \] \[ \text{Second angle: } 75 \text{ degrees} \]
Therefore, the measures of the two complementary angles are \( 15 \) degrees and \( 75 \) degrees.