ElectricPavlov

Let x= the perpindicular sides   total fence needed = 5x

the remaining LONG side of the fence (opposite the building) will then be 210 - 5x

the area will then be  x (210-5x) = 210x -5x^2 = area 

Take derivative and set to zero to find 'x' that makes biggest area:

210 -10x = 0   10x= 210  x= 21       5x = 105     Long side = 105

Total area will be    21 x 105 = 2205 sq ft    and each area will be 551.25 sq ft

Sorry!  Made a math error there!  

We are not concerned with the height...we are not stacking them......BUT WAIT....if we are arranging them on their SIDES we could put more of them on the Earth...if we place them on their NOSES, we can get even MORE ...so let's go that way....

  The the area of each car would be 45 x 80  sq inces = 3600 sq INCHES    

Now how many sq MILES is that ?      3600 in^2 / (5280 x12)^2  = .000000897 sq mi

196,900,000 sq mi /  .000000897  = 2.1957 x 10^14 cars

7.875 gms   HINT: Use the half life as 6 yrs to calculate k = -.11

1.2 x 2/5  =  1.2  x  .4 =  .48

or

1.2 x 2/5 =  1 1/5 x 2/5 = 6/5 x 2/5 = 12/25 =.48

or

1.2 x 2/5 =  2.4/5  = .48

No !       6^4 x 6^8 = 6^12

Pythag Theorem

35^2 = 26^2 + h^2     h = 23.43 inches

Cable length (single strand)  3897.27     ft      (double this (plus a little more for the turn-around) if a loop is going to be installed)

An easy way to remember this is that AREA is something squared  :   Square inches, square feet, square centimeters etc.....to GET square 'dimensions. you'll have to SQUARE something...i.e.  AREA of a circle is pi r^2       

40 x 20     = 800 sq ft

You know this is a CALCULATOR website don't you?   Just use IT !             = 1/291