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Pythagorean theorem
Find the hypotenuse of a right triangle.
Calculators / Math / Triangle geometry
Triangle geometry calculator
Calculate triangle area and perimeter from a base, perpendicular height and three sides.
On this page
Area20square units
Perimeter21units
Calculator controls
How to calculate
Calculate triangle area and perimeter from a base, perpendicular height and three sides.
Area = base*height/2; Perimeter = a+b+c
Worked example
Base: 8; Perpendicular height: 5; Side a: 8; Side b: 6; Side c: 7.
Area: 20 square units; Perimeter: 21 units.
Assumptions and limits
The area uses the entered base and its perpendicular height. The side lengths must form the same valid triangle for the perimeter to describe it.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Calculate triangle area and perimeter from a base, perpendicular height and three sides. The displayed figures use the inputs and formula shown on this page.
When this tool is useful
Use the triangle geometry to compare a scenario, check an estimate, or verify a manual calculation.
Understanding your inputs
| Input | What to enter |
|---|---|
| Base | Enter a number of at least 0.000001 and no more than 1000000000000. |
| Perpendicular height | Enter a number of at least 0.000001 and no more than 1000000000000. |
| Side a | Enter a number of at least 0.000001 and no more than 1000000000000. |
| Side b | Enter a number of at least 0.000001 and no more than 1000000000000. |
| Side c | Enter a number of at least 0.000001 and no more than 1000000000000. |
Frequently asked questions
What should I check before using the triangle geometry result?
The area uses the entered base and its perpendicular height. The side lengths must form the same valid triangle for the perimeter to describe it.
Is this triangle geometry result exact?
It is exact for the stated mathematical model and entered values. Real-world results can differ when rates, timing, fees, definitions or measurement conditions differ.