Two parallel lines are cut by a transversal. What is the measure of 1​

Both lines are parallel so using the bottom line you are given angle 7 as being 80 degrees. Angle 5 and 7 form a straight line which is 180 degrees so angle 5 would be 180-80 = 100 degrees.

Angle 1 is the same as angle 5 so angle 1 is 100 degrees.

100 degrees

B. 100°

Step-by-step explanation:

Angles 1 and 5 are corresponding angles and congruent.

Angles 5 and 7 are a linear pair and supplementary angles, so their measures add to 180°.

m<5 + m<7 = 180°

m<5 + 80° = 180°

m<5 = 100°

m>1 = m<5

m<1 = 100°

56

step-by-step explanation: