Verification of Thales Theorem – Paper triangle and parallel line setup.

Verification of Thales Theorem

Verification of Thales Theorem

Demonstrating the Basic Proportionality Theorem

Explore Thales Theorem which states that if a line is drawn parallel to one side of a triangle intersecting the other two sides, it divides those sides proportionally.

Thales Theorem
Current Step:

Click "Step 1" to begin verifying Thales Theorem.

The Geometry Behind Thales Theorem

Key Concepts:

Thales Theorem (Basic Proportionality Theorem) states:

  • If a line is drawn parallel to one side of a triangle to intersect the other two sides in distinct points
  • The other two sides are divided in the same ratio
  • If DE ∥ BC in ΔABC, then AD/DB = AE/EC
Construction Steps:
  1. Draw any triangle ABC
  2. Mark points D and E on sides AB and AC respectively
  3. Draw a line DE parallel to BC
  4. Measure and verify that AD/DB = AE/EC

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