CPM Homework Help : CC3 Problem 9-9

If $m\angle5 = 53º$ and $m\angle7 = 125º$ , find the measures of each numbered angle. Then explain how you found each angle, citing definitions and conjectures that support your steps.

Hint:

Since two of the lines are parallel, their alternate interior angles and corresponding angles are equal to each other.

More Help 1:

Angles 1, 2, and 3 form a straight angle, as do angles 4 and 5 and angles 6 and 7.

More Help 2:

$m∠7 = m∠1 + m∠2$

2 horizontal parallel lines, are crossed by 2 transversals. The transversals intersect on the upper parallel line. Angles are labeled as follows: Upper intersection of 3 lines: interior left, 1, interior middle, 2, interior right, 3. Lower left intersection of 2 lines: interior left, 4, interior right, 5. Lower right intersection of 2 lines: interior left, 6, interior right, 7.