Triangle Proportionality Theorem Worksheet
This worksheet focuses on applying the Triangle Proportionality Theorem (also known as Thales's Theorem or the Basic Proportionality Theorem) to solve for unknown lengths in triangles.
Includes
Standards
Topics
Triangle Proportionality Theorem
Name:
Date:
Score:
Read each question carefully and apply the Triangle Proportionality Theorem to find the missing lengths. Show all your work.
1. In triangle ABC, line DE is parallel to BC. If AD = 6, DB = 4, and AE = 9, find EC.
2. If a line parallel to one side of a triangle intersects the other two sides, then it divides the two sides .
3. In the triangle below, PQ is parallel to RS. If TP = 10, PR = 5, and TQ = 12, what is QS?
4
6
8
10
4. The converse of the Triangle Proportionality Theorem states that if a line divides two sides of a triangle proportionally, then it is parallel to the third side.
True
False
5. In triangle XYZ, line MN is parallel to YZ. If XM = 7, MY = 3, and XZ = 15, find XN and NZ.