Isosceles Triangle Calculator
What are the height and area of an isosceles triangle from its base and equal side? Enter the values below to calculate the result.
Result for the values shown.
Calculations run in your browser.
What to enter
| Input | Meaning and units |
|---|---|
| Side a (length) | Enter side a in length; use the same basis as the other measurements. |
| Side b (length) | Enter side b in length; use the same basis as the other measurements. |
Understanding your result
Read height (length), area (length^2), perimeter (length) in the units and model stated on this page. The formula height=sqrt(a*a-b*b/4) · area=b*height/2 · perimeter=2*a+b defines the relationship; measurement accuracy and model applicability are separate from numerical precision.
Common mistakes
- Mixing input units or changing the physical meaning of a variable without changing the model.
Check your calculation
- Use the worked example as a known reference case, then change one input at a time and check the direction and units of the response.
Calculation checks, sources and review limits
What are the height and area of an isosceles triangle from its base and equal side?
What are the height and area of an isosceles triangle from its base and equal side? Enter the values below to calculate the result.
Common uses
- What are the height and area of an isosceles triangle from its base and equal side
How it works
height=sqrt(a*a-b*b/4); area=b*height/2; perimeter=2*a+b
Worked example
Enter Side a: 5 length; Side b: 6 length. Results: height: 4 length; area: 12 length^2; perimeter: 16 length.