Question

Use slope to determine if lines PQ and RS are parallel,

perpendicular, or neither.
P(2, -1), Q(-3,-1), R(-11, 9), S(-7, 9)

Answer 1

PQ and RS are parallel to each other

Explanation:

Slope of two points (x1,y1) and (x2,y2) is given by

slope = (y2-y1)/(x2-x1)

• for two lines to be parallel slope should be equal
• for two lines to be perpendicular product of slope should be -1
• _______________________________________________

Lets find the slope of PQ and RS

for PQ P(2, -1), Q(-3,-1), R(-11, 9), S(-7, 9)

slope PQ = (-1 -(-1))/(-3 -2) = (-1 + 1)/5 = 0/5 = 0

Slope RS = (9-9)/(-7 - (-11) ) = 0/4 = 0

Since

slope PQ = slope RS = 0

Hence PQ and RS are parallel to each other