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=√(x_{2}x_{1})^{2} + (y_{2} –y_{1})^{2}

Equation of a Circle 
General Form (xh) ^{2} +( yk) ^{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(sa)(sb)(sc)) 
Horizontal Line 
Y = ( any number) 
Lateral Area of Cone 
πrsl r = radius sl = slant height 
Lateral Area Cube 
4s^{2} 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

yy_{1} = m(xx_{1}) 
Slope

Y2Y1 X_{2}X_{1 = }_{Rise over Run} 
Slope Intercept Form 
y = mx + b M = slope b = y intercept 
Surface Area of a Cone 
SA= π*radius*slant height+ πradius^{2} 
Surface Area of a Cube 
SA = 6side^{2} 
Surface Area of a Cylinder 
Lateral Area + 2πradius^{2} 
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

2πradius^{2} +2πradius x height 
Surface Area of a Right Prism 
SA = Perimeter * height + 2 Base 
Surface Area of a Sphere 
4πradius^{2} 
30 60 90 Triangle short and long legs

Short leg =½ hypotenuse Long leg = 1⁄2 hypotenuse√3 