Chapter 7 · Question 4

State the section formula for internal division.

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Q4

State the section formula for internal division.

Answer Revealed
Direct Answer:
If P(x,y)P(x,y) divides A(x1,y1)A(x_1,y_1) and B(x2,y2)B(x_2,y_2) internally in the ratio m:nm:n, then x=mx2+nx1m+nx=\frac{mx_2+nx_1}{m+n} and y=my2+ny1m+ny=\frac{my_2+ny_1}{m+n}.

Simple Explanation

Section formula gives coordinates of a point dividing a segment in a given ratio.

Exam-Ready Structure

For internal division in the ratio AP:PB=m:nAP:PB=m:n, the coordinates are P(mx2+nx1m+n,my2+ny1m+n)P\left(\frac{mx_2+nx_1}{m+n},\frac{my_2+ny_1}{m+n}\right). The weights are crossed: mm is multiplied with the coordinates of BB, and nn with coordinates of AA.

Key Points

  • If P(x,y)P(x,y) divides A(x1,y1)A(x_1,y_1) and B(x2,y2)B(x_2,y_2) internally in the ratio m:nm:n, then x=mx2+nx1m+nx=\frac{mx_2+nx_1}{m+n} and y=my2+ny1m+ny=\frac{my_2+ny_1}{m+n}.
  • Use the NCERT formula or theorem carefully.
  • Write units and final conclusion where applicable.