Chapter 7 · Question 3
How can the distance formula be used to test whether three points are collinear?
Answer
Direct Answer
Find the three pairwise distances. If the sum of two smaller distances equals the largest distance, the points are collinear.
Simple Explanation
For points on one line, one point lies between the other two, so two distances add to the third.
Exam-Ready Structure
Given points , compute , , and . If or another similar sum holds, then the three points lie on a straight line. If no such relation holds, the points are not collinear.
Key Points
- Find the three pairwise distances.