The answer is: "3" .
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Use the Pythagorean theorem (for right triangles):
a² + b² = c² ;
in which "a = "side length 1" (unknown; for which we which to solve);
"b" = "side length 2" = "√3" (given in the figure) ;
"c" = "length of hypotenuse" = "2√3" (given in the figure);
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a² + b² = c² ;
a² = c² − b² ;
Plug in the known values for "c" and "b" ;
a² = (2√3)² − (√3)² ;
Simplify:
(2√3)² = 2² * (√3)² = 2 * 2 * (√3√3) = 4 * 3 = 12 .
(√3)² = (√3√3) = 3 .
a² = 12 − 3 = 9 .
a² = 9
Take the "positive square root" of EACH SIDE of the equation; to isolate "a" on one side of the equation; & to solve for "a" ;
+√(a²) = +√9 ;
a = 3 .
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The answer is: "3" .
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