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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