If m∠6=140°, what is m∠7?
A: 140°
B: 40°
C: 50°
D: 180°
B: 40°
To find the measure of m∠7, we need to determine the relationship between m∠6 and m∠7.
In this case, we can determine the relationship by using the fact that angles which are opposite each other, formed by intersecting lines, are congruent. This is known as the Vertical Angles Theorem.
So, if m∠6 = 140°, then m∠7 will also be equal to 140°.
Therefore, the correct answer is:
A: 140°
To find the measure of m∠7, we need to use the fact that the measures of angles forming a straight line sum up to 180°.
Since m∠6 is given as 140°, we can find m∠7 by subtracting 140° from 180°:
m∠7 = 180° - 140° = 40°
Therefore, the answer is B: 40°.