# Homework Help: Trig question?

1. Aug 15, 2008

### ur5pointos2sl

Ok my math is a little rusty. I ran across a problem that states:
"A park is being considered in a space between a small river and a highway as a rest stop for travelers. Boundary BC is perpendicular to the highway and boundary AD makes an angle of 75 Deg. with the highway. BC= 160.0 m , AD= 270.0 m, and the boundary along the highway = 190.0m long. What are the length of side AB and the magnitude of angle ABC?"

I have attached a file that is almost identical to the one in the book. I need help figuring out where to start this problem(not an answer please). Any help would be appreciated.

Thanks

#### Attached Files:

• ###### Untitled.jpg
File size:
3.7 KB
Views:
165
2. Aug 15, 2008

### tiny-tim

Welcome to PF!

Hi ur5pointos2sl ! Welcome to PF!

I can't see your picture file yet, but I think the best way is probably to use x and y coordinates, starting with C as the origin.

3. Aug 15, 2008

### ur5pointos2sl

My problem is that I cant seem to use law of sine/cosine because there is always 2 things to be solved for. I think I am missing something.

I put C at the origin and looked at it that way. If i seperate the figure into two triangles that doesn't seem to lead me anywhere either. I can solve for one but then the other I am completely stuck on.

4. Aug 15, 2008

### Dick

You don't need coordinates. DO split the quadrilateral into two triangles. Solve the right triangle first. Find length of BD and the two angles. Then you have side-angle-side on the remaining triangle. Solve it.

5. Aug 16, 2008

### ur5pointos2sl

Thank you. That is exactly what I did last night except I solved for the right triangle then used law of cosine to solve for the other. I finally realized my answer was off because I was rounding to one decimal place.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook