Complementary angles are two angles whose measures add up to 90 degrees. Given that \( m∠5 = 39° \) and \( m∠6 \) is the measure of the other complementary angle, you can write the equation:
\[ m∠5 + m∠6 = 90° \]
Substituting the known value of \( m∠5 \) into the equation gives:
\[ 39° + m∠6 = 90° \]
To solve for \( m∠6 \), rearrange the equation:
\[ m∠6 = 90° - 39° \]
So, the equation to solve for \( m∠6 \) is:
\[ m∠6 = 90° - 39° \]
This simplifies to:
\[ m∠6 = 51° \]