Question

Line b passes through points (5, 5) and (10, 8). Line c passes through points (4, 8) and (1, 13). Are line b and line c parallel or perpendicular?

Answer 1

Explanation:

In going from (5, 5) to (10, 8), x (the run) increases by 5 and y (the rise) increases by 3. Thus, the slope of the line connecting the first two points is m = 3/5.

In going from (1, 13) to (4, 8), x (the run) increases by 3 and y (the rise) decreases by 5. Thus, the slope of the line connecting the first two points is m = -5/3

Because these results are negative reciprocals of one another, the two lines are PERPENDICULAR to one another.