Chapter 7 · Question 5

Derive the midpoint formula from the section formula.

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Q5

Derive the midpoint formula from the section formula.

Answer Revealed
Direct Answer:
For midpoint, ratio is 1:11:1. Substituting m=n=1m=n=1 gives P(x1+x22,y1+y22)P\left(\frac{x_1+x_2}{2},\frac{y_1+y_2}{2}\right).

Simple Explanation

The midpoint is the average of the two xx-coordinates and the two yy-coordinates.

Exam-Ready Structure

Using section formula with m=n=1m=n=1, x=x2+x12x=\frac{x_2+x_1}{2} and y=y2+y12y=\frac{y_2+y_1}{2}. Hence midpoint of A(x1,y1)A(x_1,y_1) and B(x2,y2)B(x_2,y_2) is (x1+x22,y1+y22)\left(\frac{x_1+x_2}{2},\frac{y_1+y_2}{2}\right).

Key Points

  • For midpoint, ratio is 1:11:1.
  • Use the NCERT formula or theorem carefully.
  • Write units and final conclusion where applicable.