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Enter the side length or height to instantly calculate the area of an equilateral triangle. Highly accurate results, perfect for students, teachers, and designers.
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When you need to quickly find the area of a regular triangle with three equal sides, this tool provides real-time calculations using two precise mathematical formulas. If you input the side length (a), it uses the formula A = (√3 / 4) × a². If you input the height (h), it applies A = (√3 / 3) × h². The output is a standard geometric area value (e.g., square centimeters).
Can I input both the side length and height at the same time?
No. The system automatically calculates based on a single parameter. Entering both simultaneously may cause a conflict.
Why does the result have multiple decimal places?
Because the formula involves the irrational number √3, we retain 6 decimal places to ensure engineering-level precision. You can round the result to fit your specific needs.
Only positive numbers are accepted; negative values or zero will trigger an error. The unit of the result corresponds to your input unit (e.g., inputting centimeters yields square centimeters). Ultra-high precision calculations may produce a margin of error around 0.000001, which is normal for floating-point arithmetic.
For an equilateral triangle with a side length of 5cm, the area is calculated as (√3/4) × 25 ≈ 10.825cm². If the height is known to be 4.33cm, the area is (√3/3) × 18.75 ≈ 10.825cm². We recommend teachers demonstrate the equivalence of these two calculation methods in geometry classes to help students understand the relationship between the formulas.
