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Solving the triangle

  • Thread starter msdenise15
  • Start date
1. Homework Statement
use the information to solve the triangle: b=1, c=the square root of (3)+1, B=15 degrees.
given that sin15 degrees =the square root of 6 -the square root of 2 divided by 4. FYI.. is in the square root and than add one.

2. Homework Equations
The formulas given the law of sin sinA/a=sinB/b=sinC/c
The law cosine

3. The Attempt at a Solution
I used the law of sin to find angle C. The problem is written out as the square root of (3)+1 Sin(15)/1. I came out with .70 degrees for angle c. For some reason I can't get that answer again. Also I'm not sure which formula I should be using.
 

Answers and Replies

Gib Z
Homework Helper
3,344
4
Well using the sine rule, we get [tex] \frac{\sin 15*}{1} = \frac{\sin C}{\sqrt{3}+1}[/tex].

The * I used to denote degrees. Anyway, to get the angle C, we must get Sin C by itself on one side. Once you do that, simplify the Sin 15 degrees from what it gave you in the question, and also take out a factor of sqrt2 from it. Then it should simplify very nicely, you shouldn't even need a calculator for it. You get some nice common angle, not 0.70 degrees.
 
HallsofIvy
Science Advisor
Homework Helper
41,738
897
msdenise15, you forgot to take the arcsine! What you calculated was that sin(C)= .707..= sqrt(2)/2. And, as Gibz said, that's a "well known" angle.
 

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