Square root of 100 = 10 cm. Next, 10*2 = 20^2 = 400 ft. Next, convert cm into ft, which would make 100 into about 3.3 ft. The ratio would then be about 3/400. Does that help?
You need to covert the decimal to a fraction and then if they have the same denominator then compare by the numerator if they don’t the same denominator then change so they do have one then compare
I think that there’s around 16 squares.