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Segments and Their Measures. Section 1.3. Definitions. Postulates - rules that are accepted without proof. Axioms - same as Postulates Theorems - rules that are proved. Congruent Segments - segments that have the same length. . Postulate 1: The Ruler Postulate.
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Segments and Their Measures Section 1.3
Definitions • Postulates- rules that are accepted without proof. • Axioms- same as Postulates • Theorems- rules that are proved. • Congruent Segments- segments that have the same length.
Postulate 1: The Ruler Postulate • The distance between two points is the absolute value of the difference between the coordinates.
Postulate 2Segment Addition Postulate • If B is between A and C, then AB + BC = AC. • If AB + BC = AC, then B is between A and C.
Distance Formula • If A and B are points in a coordinate plane, then the distance between A and B is:
Pythagorean Theorem • Can be used instead of the Distance Formula. a² + b² = c²
Good Example • What is the length of AB if A(-1,1) and B(3,2)?
Using Pythagorean Theorem • What is the length of AB if A(-1,1) and B(3,2)?