Free Maths Calculator

Pythagoras Calculator

Find the missing side of any right-angled triangle. Choose whether you are after the hypotenuse or a shorter side, and the calculator squares, adds or subtracts, then square roots, showing every line. Answers that are not whole numbers appear as exact surds alongside the decimal.

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    Worked Example

    A right-angled triangle has shorter sides of 3 cm and 4 cm. Find the hypotenuse.

    1. Square the two sides and add:c² = 3² + 4² = 9 + 16 = 25
    2. Square root:c = √25 = 5

    Answer: 5 cm

    Try These Yourself

    The shorter sides are 6 cm and 8 cm. Find the hypotenuse.Show answerHide answer

    Answer: 10 cm

    36 + 64 = 100, and √100 = 10.

    The hypotenuse is 13 cm and one side is 5 cm. Find the other side.Show answerHide answer

    Answer: 12 cm

    169 − 25 = 144, and √144 = 12.

    The shorter sides are 2 cm and 4 cm. Find the hypotenuse as a surd.Show answerHide answer

    Answer: 2√5 cm

    4 + 16 = 20, and √20 = √4 × √5.