Question

What is basic proportionality theorem?

Answer 1

Basic proportionality theorem.

The basic Proportionality Theorem was first stated by a Greek mathematician named Thales and hence named as Thales theorem.

Theorem: If a line is parallel to a side of a triangle that intersects the other sides into two distinct points, then the line divides those sides in proportion.

In an $∆ABC$ if $PQ\parallel BC$ then by Basic Proportionality Theorem$\frac{AP}{PB}=\frac{AQ}{QC}$.

Thus, the Basic proportionality theorem states that If a line is parallel to a side of a triangle that intersects the other sides at two distinct points, then the line divides those sides in proportion