Comprehensive Guide for Quick
Reference and Exam Prep
Diameter squared x .7854 - ✔✔Area of a circle
Diameter squared x .7854x L - ✔✔Volume of a cylinder
Pi(3.1416)x Diameter - ✔✔Circumference of circle
Half the diameter D/2 - ✔✔Radius of a circle
LxWxH - ✔✔Cubic content of square or rectangular box
Height in ft x .434 - ✔✔Psi base of water column
(H x .434) + 2lbs - ✔✔Air pressure to lift sewage
Psi x 2.31 - ✔✔Height of water column
2.31 - ✔✔Number of ft to exert 1 psi
Area x psi or
(Diameter squared in inchs x .7854) x (H in feet x .434) - ✔✔Total pressure at
base of water column
43,560 square ft - ✔✔How many square ft per acre
Diameter squared in inch x Length in ft x .0408 - ✔✔Gals in cylinderical tank
(water heater)
L"xW"xH"/231 - ✔✔Cap in Gals of square or rectangular tank in cubic inch
L'xW'xH' x 7.5 - ✔✔Cap in gals of square or rectangular tank in cubic Ft