Page 1: Calculating Lengths Using Thales' Theorem
This page demonstrates the practical application of Thales' theorem for calcul des longueurs avec Thales. The problem involves calculating lengths FD and FH in a geometric configuration where parallel lines are intersected by secant lines.
Definition: Thales' theorem states that when two lines intersect two parallel lines, the ratios of corresponding segments are equal.
Example: In the given figure, lines GH and DE are parallel, intersected by secants at point F. Using the known measurements FG=4.6,FD=9.2,FE=5.2, we can calculate FH.
Highlight: The key to solving such problems is setting up the correct proportion equation: FG/FH = FD/FE
Vocabulary: Secant lines - lines that intersect at a point
The solution demonstrates how to systematically apply the theorem by writing out the proportions and substituting known values to find the unknown lengths.