Math Help - trig triangle problem

1. trig triangle problem

Hi, there is this one problem I have and five continuations of it. I can't figure out the first problem, meaning I can't figure out the continuations. Could someone help me? And quickly preferably so I can finish my math hw? =(

The figure 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.

2. Please, this is really important. i still haven't figured it out and I need this to complete the REST of my homework!

3. Originally Posted by pyrosilver
Please, this is really important. i still haven't figured it out and I need this to complete the REST of my homework!
There's not enough information.

The answer depends on how much of the width remains after the fold.

Call that remaining width x.

Then the amount of the width that has been folded is 12 - x.

This is the opposite side of a right angled triangle with 30 degrees as its angle. We're trying to find the hypotenuse, so we use the sine ratio.

$\sin{30^\circ} = \frac{12 - x}{H}$

$\frac{1}{2} = \frac{12 - x}{H}$

$2 = \frac{H}{12 - x}$

$H = 2(12 - x)$.