Triangle Area from Three Sides (Heron's Formula): Your Questions Answered
These are the questions people ask most often about triangle area from three sides (heron's formula). Each answer is short; follow the links for the full detail.
What does a triangle area from three sides (heron's formula) calculation tell me?
Calculates the triangle area from three sides (heron's formula) from the measurements you enter. Use any unit, as long as all inputs use the same one.
What is the formula?
√(s(s−a)(s−b)(s−c)), s = (a+b+c)/2
What do I need to enter?
Side a, Side b, Side c.
Can I use any units?
Yes, as long as every input uses the same unit. The answer will be in that unit (squared for areas, cubed for volumes).
Can you show an example?
For example, with these inputs:
- Side a: 5
- Side b: 6
- Side c: 7
the calculator returns:
- Area: 14.6969
Any tips?
- Round only at the final step to avoid accumulated rounding errors.
- Estimate the answer roughly first so you can spot a result that is clearly wrong.
- Check your answer by working backwards from the result.
Background
Each formula has assumptions built in. Area formulas assume flat shapes, volume formulas assume regular solids and statistical measures assume the data you enter is the data you want to describe. Knowing the assumptions helps you pick the right tool.
Rounding is a common source of small errors. Keep full precision during intermediate steps and round only the final answer to the number of decimal places or significant figures the question asks for.
These calculations appear throughout the Singapore syllabus, from primary school percentages and fractions to secondary school algebra and geometry. Understanding the formula makes problem sums easier because you can recognise which quantity is missing.
Related calculations
- Circumference of a Circle Calculator: Calculates the circumference of a circle from the measurements you enter.
- Perimeter of a Rectangle Calculator: Calculates the perimeter of a rectangle from the measurements you enter.
- Perimeter of a Square Calculator: Calculates the perimeter of a square from the measurements you enter.
- Perimeter of a Triangle Calculator: Calculates the perimeter of a triangle from the measurements you enter.
Try it yourself with the Triangle Area from Three Sides (Heron's Formula).
Run your own numbers: Triangle Area from Three Sides (Heron's Formula)