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

Find the slope of both lines to conclude the relaion between the lines.

Slope of line bc = rise / run = [2-(-5)]/[3-4] = -7

Slope of line de = rise / run = [1-0] / [9-2] = 1/7

When the slopes of two lines, say m1 and m2 satifiies that m1xm2=-1, the lines are perendicular.

In this case, (-7) x (1/7) = -1, the you conclude that line bc and line de are perpendicular.