Question

for 20 - 21, determine which lines are parallel in the images below. 20. 21.

Explanation:

Step1: Recall parallel - line angle rules

If corresponding angles are equal, alternate - interior angles are equal, or same - side interior angles are supplementary, then the lines are parallel.

Step2: Analyze the first set of lines (20)

For the first set of lines, we have 43 - degree and 137 - degree angles. The 43 - degree and 137 - degree angles are supplementary (43+137 = 180). Also, we can observe corresponding and alternate - interior angles relationships. Line S is parallel to line T and line D is parallel to line E.

Step3: Analyze the second set of lines (21)

For the second set of lines, we have 76 - degree, 104 - degree, and 77 - degree angles. We can see that there are corresponding angles that are equal. Line S is parallel to line T.

Answer:

20: C. S || T & D || E
21: A. S || T