# Area and Perimeter

# Equilateral Triangle

Calculate the area and perimeter of an equilateral triangle. This calculator uses feet and or inches for measurements.

Equilateral triangle = a triangle with three sides of the same length.

### Equilateral Triangle Area and Perimeter

#### Calculation

- side length in feet and or inches
- decimal precision, the number of digits after the decimal point

#### Results

- the height in decimal feet
- the area of the equilateral triangle in decimal square feet
- area in square feet and inches
- the area in decimal square inches
- the area in square inches
- the area in square metres
- the perimeter of the equilateral triangle in decimal feet
- the perimeter in lineal feet and inches
- the perimeter in decimal inches
- the perimeter in inches
- the perimeter in metres

##### Formula

A = ab/4
P = 𝛑R(1+(3H)/(10+√(4-3*H)))
where A is the area of the ellipse
a length of the short diameter
b length of the long diameter
P the perimeter of the ellipse
𝛑 = 3.14159265
R = (a+b)/2
S = (a-b)/2
H = R²/S²

##### Conversions

one square foot ( ft²) = 144 square inches (in²)
one square inch (in²) = 0.00694444444444443 square feet (ft²)
one square foot ( ft²) = 0.09290304 square metres (m²)
square inch (in²) = 0.00064516 square metres (m²)

### Area and Perimeter of Various Shapes

### Changing the shape of an Area

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