Calculator 

surface area of sphere = 4 pi r^2     [* π ²][exponents]
Earth radius is 3958.8 mi
surface area of Earth = 

volume of sphere = 4/3 pi r^3       [fractions]
volume of Earth = 

Visualize area -> square       [sqrt √, simplify] [cube root...]
Earth area as a square. side = 

Earth is 29% land, 71% ocean.      [p% of x = p/100 * x]
Land on Earth = 

CONUS is 2,959,064.44 square miles of land.
percent of world's land that is CONUS =               [1/x]

Earth's orbit around sun is basically circular. C = 2 pi r = d pi
Earth distance from sun is 93M mi
distance Earth travels in one year (one revolution around sun) = 
speed in miles per hour = 

Gallon of water weighs 3778 g.     1kg = 2.2046 lbs
weight in pounds =            


Distance in km to thing at height h2 above sea level 
 given one's height h1 above sea level in meters = 3.57(√h1 + √h2)
You at 100m, distant thing 300m, what's the farthest apart they can be to be seen?
Empire State Bldg's 102nd floor observatory is 373m above street (+~50' above sea level)
   how far is the horizon?

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kilogram of water: volume is 1 liter.
Human body is 2/3 water and almost same density as water.
Your weight in kg  --> your volume in liters =
  Gallon=3.785 L   --> your volume in gallons =  

BSA m^2  = √1.15wh / 60    lbs ins       [1m^2=10.764ft^2]

BMI = 703 w/ h^2     lbs ins
body mass index

BRI = 364.2 - 365.5*√(1-(waist/(pi*height))^2)
body roundness index  3-6 is good

BMR = 10*kg +6.25*cm - 5*age + (M:5, F:-161)
day