helperid1839321, I decided to delve deeper into this subject. You may like my findings!
First of all, I think I understand why this property occurs. I happen to know that \(142857\) is the first 6 digits of the decimal expansion of \(\frac{1}{7}\). At first, I thought this was insignificant, but it turns out that this fact can be used to understand this further. Look at the table below.
| \(\frac{1}{7}=\overline{0.142857142857}\) | Multiply both sides by 10. |
| \(\frac{10}{7}=1.42857\overline{142857}\) | Let me rewrite 10/7 to make things clearer. |
| \(1+\frac{3}{7}=1.42857\overline{142857}\) | Subtract one from both sides. |
| \(\frac{3}{7}=0.42857\overline{142857}\) | WOAH! It cycles! Let's do this again. Multiply both sides by 10 again. |
| \(\frac{30}{7}=4.2857\overline{142857}\) | Rewrite 30/7 again. |
| \(4+\frac{2}{7}=4.2857\overline{142857}\) | Subtract 4 from both sides. |
| \(\frac{2}{7}=0.2857\overline{142857}\) | WOAH! The first 6 digits cycle again. You can continue the pattern, if you wish! |
This forced me to wonder if there is any more solutions for \(\frac{1}{p}\), where p is a whole number that creates this special property. This is because if another number p causes some repetition, then we would have found another number! YAY!
I decided to enlist some help from a computer here. This is what the computer outputted.
7, 17, 19, 23, 29, 47
WHAT! There are more! Yes, these have the same property. Let's check them out, shall we?
| \(p\) | \(\frac{1}{p}\) | ||
| 7 | .142857... | ||
| 17 | .0588235294117647... | ||
| 19 | .052631578947368421... | ||
| 23 | .0434782608695652173913... | ||
| 29 | .0344827586206896551724137931... | ||
| 47 | .0212765957446808510638297872340425531914893617... | ||
It appears as if 142857 is the only number that does not start with a zero. Let's keep running this simulation! Thankfully, more numbers output! I let it run for some time, too.
59, 61, 97, 109, 113, 131, 149, 167, 179, 181, 193...
In case you are wondering,
\(\frac{1}{193}\)=005181347150259067357512953367875647668393782383419689119170984455958549222797927461139896373056994818652849740932642487046632124352331606217616580310880829015544041450777202072538860103626943...
There are a few patterns that I see here
1) \(p\) must be a prime number
2) The decimal expansion must have a maximum period decimal expansion of \(p-1\).
I am also making a conjecture here that I do not know whether or not is true: there are an infinite number for p that create these types of numbers!
The triangle sum theorem states that the sum of the measures of the interior angles of a triangle equals 180 degrees. Using this theorem alone, one can find the measure of all the angles.
| \(m\angle A+m\angle B+m\angle C=180\) | Plug in the measure for all these angles by using substitution. |
| \(x-16+2x-155+\frac{1}{2}x+8=180\) | Combine like terms. |
| \(3x+\frac{1}{2}x-163=180\) | Add 163 to both sides. |
| \(\frac{6}{2}x+\frac{1}{2}x=343\) | Meanwhile, I converted 3x to a fraction that I can combine with the other lingering fraction. |
| \(\frac{7}{2}x=343\) | Multiply by 2 on both sides. |
| \(7x=686\) | Divide by 7 on both sides. |
| \(x=98\) | |
Now, plug in this value for the angle measure expressions.
\(m\angle A=x-16=98-16=82^{\circ}\)
\(m\angle B=2x-155=2*98-155=196-155=41^{\circ}\)
\(m\angle C=\frac{1}{2}x+8=\frac{1}{2}*98+8=49+8=57^{\circ}\)
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