Вот все варианты
[a , b, с]
[240, 2875, 2885.0]
[375, 2800, 2825.0]
[1000, 2400, 2600.0]
[1200, 2250, 2550.0]
[1500, 2000, 2500.0]
Ответ 5
Код программы Ruby 22
for a in 1..6000-1
for b in a..6000-1
c = (a*a+b*b)**(0.5)
p [a, b, c] if a + b + c == 6000
end
end