Triangle Calculator (SSS)
Triangle Calculator (SSS): calculate results from explicit inputs, with a formula and worked example.
Formula
- Use the units shown beside each field.
- Results update automatically whenever you change an input.
- Displayed values use up to four decimal places, or scientific notation for very small or large numbers. Calculations use standard floating-point arithmetic; exact integer and fraction tools identify their own precision rules.
- Euclidean geometry. Use one consistent length unit; areas and volumes use its square and cube. Degenerate shapes are rejected. Very thin shapes may lose floating-point precision.
Example Calculation
- Side a: 3 units
- Side b: 4 units
- Side c: 5 units
Sides 3, 4 and 5 give area 6, perimeter 12 and angles about 36.87°, 53.13° and 90°.
Method references
Frequently asked questions
How do I use this calculator?
Enter side a, side b, side c. The result updates automatically. Use Reset to restore the example values.
What method does it use?
s = (a+b+c)/2; area = √[s(s−a)(s−b)(s−c)]; cos A = (b²+c²−a²)/(2bc). Euclidean geometry. Use one consistent length unit; areas and volumes use its square and cube. Degenerate shapes are rejected. Very thin shapes may lose floating-point precision.
Why might a rounded result differ?
The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.
Are my inputs saved online?
No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.
Check the assumptions and units before using this result. Read about calculation methods.