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Expert: Sherry Wallin - 8/19/2009


Question
a boat is sailing due east parallel to the shoreline at a speed of 10 miles per hour. At a given time the bearing to the lighthouse is S 70 degrees E, and the 15 minutes later the bearing is S 63 degrees E.Find the distance from the boat to the shoreline if the lighthouse is at the shoreline.

http://i763.photobucket.com/albums/xx275/trinhkieu888/9.jpg

this is a picture that my book gave me. Thank you for your help!

Answer

law of sines
T~
    Interesting how different people see things differently. I drew a different diagram and then I saw you had drawn one so I just added a few details to yours and am sending it back. Using geometry I filled in a few other useful angles and then just used the Law of Sines to solve the problem. You needed to use the fact that the boat was traveling at 10mph for 15 min or 1/4 of an hour to get the distance traveled was 2.5 mi which is one side of the triangle you will use with your Law of Sines equation. If you need/want more explanation feel free to ask me.

Math Prof

Sherry Wallin

Expertise

I can answer most questions up through Calculus and some in Number Theory and Abstract Algebra.

Experience

I have had my Bachelor's Degree since 1987 and have been a teacher since 1988. I earned my Masters Degree in Mathematics May 2010. I have been teaching at the same community college since 2002.

Education/Credentials
I have taught 12 years at the community college level, medical college, and technical college as well as a high school instructor and alternative education instructor and charter school instructor.

Awards and Honors
Master's GPA 3.56 Bachelor's GPA 3.34 Post grad work not degree related GPA 4.0

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