Geometry Formulas

List of Geometry Formulas Chart

Area of a Circle


A = Π x square of radius

Area of Equilateral Triangle




A = (side^2) √3)/4

Area of n gon

A = ½ apothem * Perimeter

Area of a Parallelogram


A= base x height

Area of a Rectangle

A = length x width

Area of a Rhombus

A = ½ Diagonal 1* Diagonal 2


Area of a Square

A = Side^2

Area of a Trapezoid

A = ½ ( Base1 + Base 2 ) height

Area of a Triangle

A = ½ Base x Height

Base Area of Heptagon

Area of Base = ½ apothem * perimeter

Base Area of Hexagon

Area of Base = ½ apothem * perimeter

Base Area of Octagon

Area of Base = ½ apothem * perimeter

Base Area of Parallelogram

Area of Base = base * altitude

Base Area Pentagon

Area of Base = ½ apothem * perimeter

Base Area Rectangle

Area of Base = length * width

Base Area Square

Area of Base = Square of side

Base Area Trapezoid

Area of Base = ½ (height)(base 1 + base2)

Base Area Triangle

Area of Base = 1/2base * height

Circumference of a Circle

C =2 x Π x radius


Distance Formula

D=√(x2-x1)2 + (y2 –y1)2


Equation of a Circle

General Form (x-h) 2 +( y-k) 2 h and K are coordinates of the circle and r = radius


45 45 90 Triangle Hypotenuse

H= leg√2

45 45 90 Triangle Legs


1⁄2 hypotenuse√2

Heron’s Formula




s=(a+b+c)/2 then A= √(s(s-a)(s-b)(s-c))

Horizontal Line

Y = ( any number)

Lateral Area of Cone

πrsl r = radius sl = slant height

Lateral Area Cube

4s2 s=side


Lateral Area Cylinder


Circumference x Height


Lateral Area Prism

Perimeter x height


Lateral Area Pyramid

1/2P * sl sl =slant height P=perimeter


Lateral Area Rectangular Solid

Perimeter *height


Lateral Area Right Cone

LA = ½ Psl P=2πr sl = slant height


Lateral Area Right Cylinder

LA = 2πr*h


Lateral Area Right Prism

LA = Ph P = sum of base sides h = height

Midpoint Formula




( X1 + X2)/2 , (Y1 + Y2)/2

Perimeter of a Parallelogram

P= 2( base + side)

Perimeter of a Rectangle

P= 2(base + height)

Perimeter n gon

P = number of sides * sides

Perimeter of a Rhombus

P= 4 x side

Perimeter of a Square

P = 4 x side

Perimeter of a Trapezoid

Base1 + Base2 + Side1 + side 2

Perimeter of a Triangle

Side A + Side B + Side C

Point Slope Form


y-y1 = m(x-x1)







X2-X1 = Rise over Run

Slope Intercept Form

y = mx + b M = slope b = y intercept

Surface Area of a Cone

SA= π*radius*slant height+ πradius2

Surface Area of a Cube

SA = 6side2

Surface Area of a Cylinder

Lateral Area + 2πradius2

Surface Area of a Prism

Lateral Area + 2Base

Surface Area of a Pyramid

Lateral Area + 1Base

Surface Area of a Rectangular Prism

2(length*width + length*height + height*width)

Surface Area of a right Cone



SA=1/2*Diameter*π*slant height+base

Surface Area of a Right Cylinder



2πradius2 +2πradius x height

Surface Area of a Right Prism

SA = Perimeter * height + 2 Base

Surface Area of a Sphere


30 60 90 Triangle short and long legs



Short leg =½ hypotenuse

Long leg = 1⁄2 hypotenuse√3