###
perimeter of a square

P = 4 × S

###
perimeter of a rectangle

P = 2×L⁺2×W

###
area of a rectangle

A = L×W

###
circumference of a circle (use when you know the radius)

C = 2 ¶ R

###
circumference of a circle (use when you know the diameter)

C = ¶ × D

###
area of a circle

A = ¶ × R²

###
area of a parallelogram

A = B ×H

###
area of a triangle 1

A = B × H ÷ 2

###
area of a triangle 2

A = ½ × B × H

###
volume of a rectangular prism

V = L × W × H

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