How to use the isosceles triangle calculator
Find the height, area and apex angle of an isosceles triangle from its base and leg lengths. Enter base length, leg length in the fields above; the height to base, area, apex angle are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “isosceles triangle area”, “isosceles height”, “apex angle calculator”, “calculate isosceles triangle”, “find height to base”.
Formula
Variables
- b — Base length (cm)
- l — Leg length (cm)
Worked example
With base length = 6 cm, leg length = 5 cm, the calculator gives height to base ≈ 4 cm; area ≈ 12 cm²; apex angle ≈ 73.7398 °.
Frequently asked questions
What is the isosceles triangle calculator used for?
Find the height, area and apex angle of an isosceles triangle from its base and leg lengths. It helps with questions such as “isosceles triangle area”, “isosceles height”, “apex angle calculator”.
What is the formula for the isosceles triangle calculation?
Height to base (cm) = √(l × l-(b / 2)^2). Area (cm²) = b × [Height to base] / 2. Apex angle (°) = 2 × asin(b / 2 / l). Here b is base length (cm), l is leg length (cm).
What inputs do I need for the isosceles triangle calculator?
You need base length in cm, leg length in cm. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the isosceles triangle calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the isosceles triangle result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.