The Pythagorean Theorem and the Distance Formula

Concept

Pythagorean Triple

A Pythagorean triple, commonly written as (a,b,c), is a set of three natural numbers that satisfy the Pythagorean Theorem. a^2+b^2=c^2 A right triangle can be drawn using the numbers of a Pythagorean triple as its side lengths. The lowest valued set of numbers that form a Pythagorean triple are 3, 4, and 5. There are infinitely many Pythagorean triples. The following table shows a few.

Triple Substitute in a^2+b^2=c^2 Simplify
( 3, 4, 5) 3^2+ 4^2? = 5^2 9+16=25 ✓
( 5, 12, 13) 5^2+ 12^2? = 13^2 25+144=169 ✓
( 8, 15, 17) 8^2+ 15^2? = 17^2 64+225=289 ✓
( 7, 24, 25) 7^2+ 24^2? = 25^2 49+576=625 ✓

If (a,b,c) is a Pythagorean triple, then so is (ka,kb,kc) for any natural number k.

(a,b,c) k (ka,kb,kc)
( 3, 4, 5) 3 ( 3( 3), 3( 4), 3( 5))

(9,12,15)
( 5, 12, 13) 2 ( 2( 5), 2( 12), 2( 13))

(10,24,26)
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