perimeter of square
P = 4s
perimeter of rectangle
P = 2l + 2w
perimeter of triangle
P = a + b + c
area of square
A = s^2
area of rectangle
A = lw
area of triangle
A = 1/2bh
circumference of circle
C = πd
area of circle
A = πr^2
surface area of cube
SA = 6s^2