Three-dimensional trigonometry question

[JamesGoh]

Homework Statement

See the document attached as it contains a diagram

Homework Equations

cos(theta) = adjacent/hypotenuse, sin(theta) = opposite/hypotenuse, tan(theta) = opposite/adjacent

The Attempt at a Solution

See document attached

 

[HallsofIvy]

People who do not happen to have Microsoft Office cannot open your attachment.

 

[Mark44]

Your drawing and work are incorrect. Here's a quick drawing I did using Whiteboard. I wrote an equation using the lengths I show on the right edge, which gives me an equation involving $sin(\theta)$ and $cos(\theta)$. The tricky part, which leads to the answer you show, is to combine those two terms into the sine of a sum of two angles. I neglected to put in the width of the inner rectangle, which is 8.

To add to what HallsOfIvy said, we ask that you not put your work into a proprietary file format. For one thing, some people don't have Word and can't see what you did. For another thing, posting an image of your work is also frowned on, as it makes it more difficult for people helping you to identify exactly where you have gone wrong.

The text in your Word document should have been posted directly in the page, and your sketch could have been uploaded separately, or you could use our new feature, Whiteboard, as I did.