45 45 90 triangle calculator

A 45–45–90 triangle has two equal legs and a hypotenuse equal to either leg × √2.

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Either equal leg

Answer

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A 45–45–90 triangle has two equal legs and a hypotenuse equal to either leg × √2.

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Precision and calculation record

Decimal places in numeric results and text downloads

Rounding changes displayed numbers, not the calculation. Text, fractions, matrices and CSV schedules keep their own formatting. Automatic keeps up to 12 significant digits, with money shown to cents where applicable.

Step-by-step calculation

Inputs are substituted below. Each line evaluates the next operation; intermediate values are displayed to 12 significant digits while the calculation uses full precision.

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Formula and assumptions

The input is a leg, not the hypotenuse. All returned lengths share your input unit; the area uses squared units.

Automatic precision shows numbers to 12 significant digits. Thousands separators such as 1,000 are accepted; use a dot for decimals.

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Updated 2026-09-26

Using 45 45 90 triangle calculator

A 45–45–90 triangle has two equal legs and a hypotenuse equal to either leg × √2.

The input is a leg, not the hypotenuse. All returned lengths share your input unit; the area uses squared units.

Next: Basic calculator

A worked example

With either equal leg = 3, the hypotenuse is 4.242640687119286.

Before you use the result

The input is a leg, not the hypotenuse. All returned lengths share your input unit; the area uses squared units.

Example results for either equal leg

These examples use the formula above. They are reference calculations, not recommended settings.

Either equal leg	Hypotenuse
1.5	2.12132034356
3	4.24264068712
6	8.48528137424

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ToolOctopus. “45 45 90 triangle calculator.” Updated 2026-09-26. https://tooloctopus.com/45-45-90-triangle-calculator.

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