Find the missing side of a right triangle.
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Full disclaimerThe Pythagorean theorem says that in a right triangle the square of the hypotenuse equals the sum of the squares of the legs: a² + b² = c². The calculator finds the hypotenuse as √(a² + b²) or a missing leg as √(c² − a²), checking that the hypotenuse is longer than the known leg. For legs of 3 and 4 the hypotenuse is 5.
Square both legs, add them and take the square root: c = √(a² + b²). For legs of 3 and 4 you get √(9 + 16) = √25 = 5. The calculator does this automatically when you choose the hypotenuse as the unknown side.
Subtract the square of the known leg from the square of the hypotenuse and take the root: b = √(c² − a²). For a hypotenuse of 5 and a leg of 3 you get √(25 − 9) = √16 = 4. The hypotenuse must be longer than the leg, otherwise the calculator shows an error.
METHOD
a²+b²=c², where c is the hypotenuse.
TRACEABLE
Basic arithmetic or geometry using the formula shown. Uses only your inputs.
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