**You are at the section Fun With Math-General Stuff**
# Formulas: Trigometry and Geometry

### NOTE: pi = 3.14159265358979323846

## Perimeters/Circumferences (2-D)

**Circle:** Circumference = pi * diameter

**Rectangle:** Perimeter = 2 * length + 2 * width

**Square:** Perimeter = 4 * side

**Triangle:** Perimeter = 3 * side

**Regular Hexagon:** Perimeter = 6 * side

**Trapezoid:** Perimeter = 2 * aside + 2 * bside

**Note:** aside and bside are measurements of two consecutive sides of the trapezoid.

## Diagonals (2-D)

**Diamond Square:** side = SQR(diag

^{2}/2)

**Square:** Diagonal = (side

^{2} * 2)

^{1/2} or SQR((side

^{2} * 2))

**Circle:** Diameter = radius * 2, radius = diameter/2

**Rectangle:** Diagonal = (length

^{2} * width

^{2})

^{1/2}
**Triangle (Perfect):** Height = (side * SQR(3))/2

## Areas (2-D)

**Triangle:** Area = (base * height) / 2

**Triangle (Perfect):** Area = (side/2)

^{2} * SQR(3)

**Triangle (Perfect):** Area = SQR (side

^{2} - (side/2)

^{2})

**Diamond Square:** AREA = diagonal

^{2}/2

**Square:** Area = side

^{2}
**Rectangle:** Area = length * width

**Parallelgram:** Area = base * height

**Trapezoid:** Area = height * (base1 + base2)/2

**Wrecktangle:** Divide into two triangles and use triangle forula to combine

**Circle:** Area = pi * radius

^{2}
**Ellipse:** Area = pi * a * b

**Trapezoid:** Area = (height*(aside + bside))/2

**Note:** aside and bside are measurements of two consecutive sides of the trapezoid.

**Regular Pentagon:** Area = 1.720 * side

^{2}
**Regular Hexagon:** Area = 2.598 * side

^{2}
**Regular Hexagon:** Area = 3 * (side/2)

^{2} * SQR(3)

**Regular Octagon:** Area = 4.828 * side

^{2}
## Edge Length (3-D)

**Cube:** Edge = side * 12

**Rectangular Prism:** Edge = length * 4 + width * 4 + height * 4

**Tetrahedron (4-sided Triangular Figure):** Edge = side * 6

## Diagonals (3-D)

**Cube:**
## Surface Areas (3-D)

**Cube:** Area = side

^{2} * 6

**Rectangular Prism:** Area = 2 * (length * width + width * height + height * length)

**Tetrahedron:** Area = (base * height) * 2

**Sphere:** Area = radius

^{2} * pi * 4

## Volume (3-D)

**Cube:** Volume = side

^{3}
**Rectangluar Prism:** Volume = length * width * height

**Pyramid:** Volume = (AreaOfBase * height)/3

**Cylinder:** Volume = pi * r

^{2} * height

**Cone:** Volume = (pi * r

^{2} * height)/3

**Sphere:** Volume = (4 * pi * r

^{3})/3

## Temperature Conversions

Celsius = (Fahrenheit - 32) / 1.8

Fahrenheit = (Celsius * 1.8) + 32

Absolute Zero = -273.16 degrees Celsius or Zero degrees Kelvin!

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