Fatima plotted one side of a heptagon on a grid. The points (–8, 1) and (–8, 8) are joined to form a side of the heptagon. Fatima says that this side is a vertical line segment that is 9 units long.What is Fatima’s error?

The points have the same x-coordinate, −8, so the segment is vertical. Its length is the difference between the y-coordinates: 8 − 1 = 7 units. Fatima’s error was saying the segment is 9 units long; it measures 7 units, as choice B states.

AI-written and checked against the verified answer.