Area of a equilateral triangle calculator
Enter the dimensions of a equilateral triangle and read off its area, its perimeter and the quantities that follow from them.
Area
15.588 457m²
- Perimeter
- 18
- Height
- 5.196 152 4
- Inradius
- 1.732 050 8
- Circumradius
- 3.464 101 6
Show the working
- Side = 6
- Area = sqrt(3)/4 * 6^2 = 15.5885
- Perimeter = 3 * 6 = 18
- Height = 6 * sqrt(3)/2 = 5.196 15
- Inradius = 6 / (2*sqrt(3)) = 1.732 05
- Circumradius = 6 / sqrt(3) = 3.4641
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- area = (sqrt 3 / 4) s^2
- height = (sqrt 3 / 2) s
Lengths are entered in metres by default; switch any field to feet, inches or millimetres and the conversion is exact.