Hello Monica. Good work. Excellent, even :-) When I answered this same problem some time back, I took a slightly different path, but we both ended up at the same place, namely 104 gallons of paint. I was happy to see someone else's answer was consistent with mine, because there was a "solution" even earlier than mine that ended with a different (read incorrect) answer. Here's how I did it:
You're going to have to convert those meters to square feet,
so I think it's better to do it from the start. Even though we'll
have fractions to contend with, a calculator makes that easy.
12 m
1 foot is 0.3048 meter, so the height is ––––––––– = 39.3701 ft
0.3048 m/ft
120 m
1 foot is 0.3048 meter, so the length is ––––––––– = 393.7007 ft
0.3048 m/ft
Area is height times length (39.3701 ft)(393.7007 ft) = 15,500.0359 sq ft
1 gallon will cover 150 sq ft
so divide that into the area 15,500.0359 sq ft
––––––––––––––– = 103.3335 gallons
150 sq ft/gallon
You can't buy just part of a gallon of paint,
so we have to round that up to whole gallons 104 gallons
.