# Example 14 - Chapter 7 Class 10 Coordinate Geometry

Last updated at Feb. 25, 2017 by Teachoo

Last updated at Feb. 25, 2017 by Teachoo

Transcript

Example 14 Find the value of k if the points A(2, 3), B(4, k) and C(6, –3) are collinear. If the above points are collinear, they will lie on the same line, i.e. they will not form triangle Therefore, Area of ∆ABC = 0 1/2 [ x1(y2 – y3) + x2(y3 – y1) + x3(y1 – y2) ] = 0 Here x1 = 2 , y1 = 3 x2 = 4 , y2 = k x3 = 6 , y3 = −3 Putting values 1/2 [ 2(k – (−3)) + 4(−3 − 3) + 6(3 – k) ] = 0 2(k + 3) + 4(−6) + 6(3 − k) = 0 × 2 2k + 6 – 24 + 18 – 6k = 0 2k – 6k = − 6 + 24 −18 −4k = 0 ⇒ k = 0

Chapter 7 Class 10 Coordinate Geometry

Concept wise

- Distance Formula
- Equidistant points
- Checking points collinear or not
- Type of triangle formed
- Type of quadrilateral formed
- Section Formula- Finding coordinates
- Section Formula- Finding coordinates of a point in a quadrilateral
- Finding ratio
- Area of triangle
- Given area, finding k
- Area of quadrilateral

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.