PYTHAGORAS CALCULATOR
CHOOSE MISSING SIDE • ENTER TWO KNOWN SIDES
RIGHT TRIANGLE INPUTS
Use NEXT for the answer, then WORKING for full square-root steps.
PYTHAGORAS ANSWER
MISSING RIGHT-TRIANGLE SIDE
FULL WORKING
SQUARES • SUBSTITUTION • SQUARE ROOT
Use PREVIOUS for the answer, or NEXT for formula help.
PYTHAGORAS FORMULA
RIGHT TRIANGLE RULE
Formula: c² = a² + b².
Hypotenuse: c is opposite the right angle.
Shorter sides: a and b are the two legs.
Use this only for right-angled triangles.
FIND THE HYPOTENUSE
WHEN a AND b ARE KNOWN
Formula: c = √(a² + b²).
Square side a and square side b.
Add the two square values together.
Take the square root to find c.
FIND A SHORTER SIDE
WHEN c AND ONE LEG ARE KNOWN
Find side a: a = √(c² − b²).
Find side b: b = √(c² − a²).
Square the hypotenuse, subtract the known shorter-side square.
The hypotenuse must be the longest side.
WHAT THIS TOOL DOES
RIGHT TRIANGLE MISSING SIDE FINDER
This calculator finds a missing side in a right triangle.
It can find the hypotenuse or either shorter side.
It shows the formula, substitution and square-root working.
It is built for GCSE maths and homework checking.
HOW TO USE
CHOOSE MISSING SIDE • ENTER TWO VALUES
Choose which side is missing: c, a or b.
Enter the two known side lengths using the same unit.
Press SOLVE or Enter to calculate.
Use NEXT BOX or tap a field to switch input boxes.
WORKED EXAMPLES
HYPOTENUSE AND SHORTER SIDE
Find c: a = 6 and b = 8.
c² = 6² + 8² = 36 + 64 = 100.
c = √100 = 10.
Find a: c=10, b=8 gives a=√(100−64)=6.
COMMON SEARCHES
SEARCH INTENT COVERAGE
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MORE SEARCHES
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WHO USES IT
STUDENTS • TEACHERS • PARENTS
Students use it to check Pythagoras answers and square-root steps.
Teachers use it to demonstrate right-triangle examples.
Tutors use it for GCSE revision and homework support.
Parents can use it to support right-triangle maths homework.
COMMON USE CASES
DIAGONALS • RAMPS • DISTANCES
Use it for diagonals, ladders, ramps and right-angle distances.
Use it for map problems, construction checks and exam practice.
Use it when a question gives two sides of a right triangle.
Do not use it for triangles without a right angle.
RELATED TOOLS
GEOMETRY AND TRIANGLE LINKS
Pythagoras connects with triangle solving, trigonometry and geometry.
FAQ + SEARCH TERMS
READABLE FINAL SEO PAGE
Does it work for any triangle? No, only right triangles.
Which side is c? c is the hypotenuse.
Can c be shorter? No, c must be the longest side.
right triangle calculator • hypotenuse finder • missing side calculator
Pythagoras theorem help • geometry side length calculator