To find the measure of angle \( m∠7 \), we can use the fact that angles that are on a straight line (linear pairs) sum up to \( 180^\circ \).
Since \( m∠6 = 140^\circ \), we can find \( m∠7 \) as follows:
\[ m∠6 + m∠7 = 180^\circ \]
Substituting the known value:
\[ 140^\circ + m∠7 = 180^\circ \]
Now, subtract \( 140^\circ \) from both sides:
\[ m∠7 = 180^\circ - 140^\circ \] \[ m∠7 = 40^\circ \]
Therefore, the measure of \( m∠7 \) is \( 40^\circ \).
The correct response is 40°.