Use the image to answer the question.

An illustration shows two parallel slanting lines m and l intersecting a vertical line k. The angles formed at the intersection of lines l and k are 1, 2, 4, and 3. The angles 1 and 4 are opposite to each other while angles 2 and 3 are opposite to each other. The angles formed at the intersection of lines m and k are 5, 6, 8, and 7. The angles 5 and 8 are opposite to each other while angles 6 and 7 are opposite to each other.

If m∠6=140°
, what is m∠7
?

(1 point)
Responses

140°
140 degrees

180°
180 degrees

50°
50 degrees

40°

1 answer

To find \( m∠7 \), we can use the property that angles on a straight line sum up to \( 180° \).

Since \( ∠6 \) and \( ∠7 \) are adjacent angles, we know:

\[ m∠6 + m∠7 = 180° \]

Given that \( m∠6 = 140° \), we can substitute this value into the equation:

\[ 140° + m∠7 = 180° \]

Now, we can solve for \( m∠7 \):

\[ m∠7 = 180° - 140° = 40° \]

Thus, the measure of angle \( ∠7 \) is:

\[ \boxed{40°} \]