Question

Line BC contains points B (4, −5) and C (3, 2). Line DE contains points D (2, 0) and E (9, 1). Lines BC and DE are

Answer 1

perpendicular, because their slopes are negative reciprocals.

Answer 2

Line BC :
(4,-5)(3,2)
slope = (2 - (-5) / (3 - 4) = (2 + 5)/ -1 = -7

Line DE:
(2,0)(9,1)
slope = (1-0) / (9 - 2) = 1/7

these are negative reciprocal slopes and therefore, perpendicular lines