Any fraction with a denominator factor that is something other than 2 or 5 will be a repeating decimal.
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Most calculators will not show the 18-digit repeat of 3/19, since they display fewer digits than that. You have to know that a denominator factor of 19 will result in a repeat that can be as long as 19-1 = 18 digits.
to go through the origin, it must pass through (0,0); thus if we plug in 0 for x and 0 for y we are left with 4 + 12(z) = 0, solve for z and we get -1/3
