If you are referring to 16 feet by 30 feet the formula would simply be 16x30=480.If it were inches, the formula is 16x30=480 divided by 144 = 3.333 square feet. The 144 is a constant in that formula.
16X30=480 SQ'
To calculate square feet, multiply one dimension by the other. A room of these dimensions, 16 ft by 30 ft would be 480 square feet. - wjs1632 -
While the heater manufacturers have all kinds of charts and graphs, as a pool service provider in the desert southwest U.S., I can tell you that you want at LEAST 300,000 BTU's, depending on your local climate. In colder areas where you need to heat the water from a lower starting temperature, I would recommend 400,000 BTU's (about as big as they get for residential pools). The initial expense is slightly higher for the larger units, however, they tend to heat the water with more fuel efficiency as they make the water hotter, faster, thereby requiring the unit to burn fuel for less time.
The easiest way to find the GCF (in my opinion) is to find out what numbers mulitply to 90 and 480:90: 1x90; 2x45; 3x30; 5x18; 6x15; 9x10(You know you can stop at 9x10 because after 10, at 6x15, is 15. The numbers go in order if you list it out: 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90)You can do the same thing for 480.480: 1x480; 2x240; 3x160; 4x120; 5x96; 6x80; 8x60; 10x48; 12x40; 15x32; 16x30You can stop at 16x30 because when you compare it with the factors with 90, you can see that 480 does not have any factors with 90 and 45, so the next highest is 30.Answer: 30