# Sine rule help! + pics

• Jun 22nd 2009, 03:01 AM
kiwiNCFC
Sine rule help! + pics
Hi everyone, new user on here!

I have an assignment in tomorrow which i have been trying to do for months! I will give you the question and hopefully some of you might be able to help me, i will also include a picture i drew :)

Question

"In the diagram below (Fig 1)AB is the inclined jib of a crane and is 10m long. AC is 4m long. Using the sine rule, calculate the inclination of the jib to the vertical and the length of tie CB. "

Diagram: http://img36.imageshack.us/img36/916/mathsquestion.png

Sorry its soo big. I hope someone can help me!
• Jun 22nd 2009, 04:10 AM
stapel
If the angle at C (the one on top of the upper slanty line) is 120 degrees, then the angle below is 60 degrees.

You have a side with length 10 and the measure of the angle opposite. You have a side with length 4 and you need the measure of the angle opposite.

Plug this information into the Law of Sines, and solve for the needed angle measure. (Wink)
• Jun 22nd 2009, 04:44 AM
kiwiNCFC
Thanks i think i have nearly got it!