Chapter 6 · Question 2

State the Basic Proportionality Theorem.

Answer

Direct Answer

If a line is drawn parallel to one side of a triangle to intersect the other two sides in distinct points, then it divides those two sides in the same ratio.

Simple Explanation

A line parallel to one side cuts the other two sides proportionally.

Exam-Ready Structure

In

\triangle ABC

, if a line through points

D

on

AB

and

E

on

AC

is parallel to

BC

, then

\frac{AD}{DB}=\frac{AE}{EC}

. This is the Basic Proportionality Theorem, also called Thales theorem.

Key Points

If a line is drawn parallel to one side of a triangle to intersect the other two sides in distinct points, then it divides those two sides in the same ratio.