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The figure below shows a long rectangular strip of paper, one corner of which has been folded over to meet the opposite edge, thereby creating a 30-degree angle. Given that the width of the strip is 12 inches, find the length of the crease.

enter image description here

I labeled the side opposite to the $30^{\circ}$ angle as $x$ and the hypotenuse side would be $y$. The value for $x$ would be $y\sin(30) = x$. I also know that the hypotenuse of the smaller right triangle formed after the crease is also $x$ and the remaining width on the right would be $12-x$.

To solve for $y$, I thought of using the $\cos(60) = \frac{12-y\sin(30)}{y\sin(30)}$. The trouble is trying to find the value of $y$ from the cosine ratio of 60. I would appreciate it if someone can help me with that.

Thank you!

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    $\begingroup$ What is the problem? $\cos 60°=\sin30°=1/2$. Solve the equation to find $y=16$. $\endgroup$ – Aretino Nov 11 '17 at 16:31
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The length of the crease is 16 inches. enter image description here

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Hint:

enter image description here

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