Pythagoras & Right Triangle Calculator
Solve a right-angled triangle from two sides or a side and an angle — sides, angles, area and sin, cos, tan.
Result
How to use
- 1
Choose what you already know about the right triangle.
- 2
Type the two values (angle in degrees).
- 3
See every side, both angles, the area and the trigonometric ratios.
Questions
What is Pythagoras' theorem?
In a right-angled triangle, the square of the hypotenuse equals the sum of the squares of the other two sides: c² = a² + b². For 3, 4 and 5: 9 + 16 = 25.
What are sin, cos and tan?
For angle A: sin A = opposite ÷ hypotenuse, cos A = adjacent ÷ hypotenuse and tan A = opposite ÷ adjacent (remember SOH-CAH-TOA).
What is a Pythagorean triple?
Three whole numbers that fit c² = a² + b², like 3-4-5, 5-12-13, 8-15-17 and 7-24-25. Any multiple, such as 6-8-10, also works.
About this Pythagoras tool
Pythagoras & Right Triangle Calculator — Solve a right-angled triangle from two sides or a side and an angle — sides, angles, area and sin, cos, tan. It is one of 200 free tools on namasivayam.in, made by software engineer Namasivayam Vadivelan for everyday use in India.
Everything is calculated instantly in your browser: nothing you type or upload is sent to any server, there is no sign-up, and it works on mobile and desktop. Choose what you already know about the right triangle.
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Results are estimates to help you plan. They are not financial, tax or medical advice.