HardMathematicsHigh School (9–10)GeneralCoordinate Geometry › Distance, Midpoint and Section FormulaeNumericalBoard ExamSAT
For what value of k do A(-1, 4), B(1, 1) and C(5, k) lie on one straight line?
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
For what value of do , and lie on one straight line?
Need a reminder? The key ideaShow
Compare the squares of the sides to name a triangle: equal sides make it isosceles, and gives a right angle. Area , which is for collinear points.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The steady rate. For each step of in , falls .
Step 2. From to . rises , so falls : .
Step 3. Check with the area. at .
Answer: .
Discussion (0)
Log in to join the discussion.
Loading…