Skip Navigation Links
Similar Triangles: Converse of Proportionality Theorem
To enroll in any of our courses, click here
Similar Triangles: Converse of Proportionality Theorem
You know that the converse of the basic proportionality theorem is true.
Example: For fig.1, state if PQ EF.
Solution: DP/DE = 3.9/3 = 13/10 and
DQ/QF = 3.6/2.4 = 3/2

therefore, PQ is not parallel to EF.

Example: In fig.2, EF || AB || DC.
Prove that
Solution: From ADC, we have
EP DC (EF DC given)
Therefore, AE/ED = AP/PC (1)
Also, from CAB, we have
FP BA (EF AB given)
Therefore, BF/FC = AP/PC
Therefore, from (1) and (2),
People who saw this lesson also found the following lessons useful:
Eliminating Method by Equating Coefficients
Quadratic Equation
Trigonometric Ratios and Identities
As many of you know, Winpossible's online courses use a unique teaching method where an instructor explains the concepts in any given area to you in his/her own voice and handwriting, just like you see your teacher explain things to you on a blackboard in your classroom. All our courses include teacher's instruction, practice questions as well as end-of-lesson quizzes for practice. You can enroll in any of our online courses by clicking here.

The format of Winpossible's online courses is also very suitable for teachers who are using an interactive whiteboard such as Smartboard on Promethean in their classrooms, because the course lessons can be easily displayed on such interactive whiteboards. Volume pricing is available for schools interested in our online courses. For more information, please contact us at

 Copyright © Winpossible, 2010 - 2011
Best viewed in 1024x768 & IE 5.0 or later version