Răspuns:
Explicație pas cu pas:
a/4 = 4b/13 = c/2 = d/1
a²+b²+c²+d² = 505
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c = 2d ; b = 13d/4 ; a = 4d =>
(4d)²+ (13d/4)² + (5d)² + d² = 505 =>
16d²+ 169 d²/16 + 25d² + d² = 505 =>
42d² + 169d²/16 = 505 I·16 =>
672d²+169d² = 8080 =>
841 d² = 8080 => d² = 8080/841
d = √8080 / 29 =>
d = 4√505 /29
c = 8√505 /29
a = 16√505 /29
b = 13√505 /29