Casey, Terry and Grace went trick-or-treating on Halloween. They got a total of 340 pieces of candy. Casey got 24 more pieces of candy than Terry. Casey got 3 times more candy than
Grace. How many pieces of candy did each person get?

step-by-step explanation:

points a and b are equidistant from the desired line, so the line you find by using them will go through point r.

using points other than a and b will give the desired line only if they are equidistant from r. if they are randomly located, the perpendicular line you create will not necessarily go through point r, hence will not be a solution to the problem.

0.2cm < 1.5cm : 0.2cm > 1.5cm