Spike's Calculators

# Pentagram

Calculate the area and perimeter of a pentagram.
This calculator uses feet and or inches for measurements.

Pentagram = a five-pointed star that is formed by drawing the diagonals in a pentagon.

### Pentagram Area and Perimeter

Point to Point Length ft in n
d
Decimal Precision

#### Results:

###### Area of the Pentagram
Decimal Square Feet ft²
Square Feet ft² in²
Decimal Square Inches in²
Square Inches in²
Square Metres
###### Perimeter of the Pentagram
Decimal Feet ft
Feet ft in
Decimal Inches in
Inches in
Metres m

#### Calculation

1. the length of a side in feet and or inches
2. decimal precision, the number of digits after the decimal point

#### Results

1. the area of the pentagram in decimal square feet
2. area in square feet and inches
3. the area in decimal square inches
4. the area in square inches
5. the area in square metres
6. the perimeter of pentagram in decimal feet
7. the perimeter in lineal feet and inches
8. the perimeter in decimal inches
9. the perimeter in inches
10. the perimeter in metres

##### Formula
```A = √5(5-2√5w²/2
P = v*10
where A is the area of the pentagram
P the perimeter of the pentagram
v = s/((1+√5)/2)
u = v/((1+√5)/2)
w = v+u
s the length of a side
```

##### 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)
```