# Trigonometry /Logarithms (brace yourself)

posted by
**Anon**
.

This is an outline that i have to use to find the solution of the question. It involves logarithms and half-angle formulas.I have worked though it but got stuck on some parts. I'd like if you look over my work.

solve the triangle for which given parts are

a=27 ,b=21 ,c=24

Now i used the cosine law and got the answers

A=73 deg 23' 55"

B=48 deg 11' 23"

C=58 deg 24' 43"

...................

okay now for this outline;

a=27

b=21

c=25

----

2s=73

s=36.5

s-a=9.5

s-b=15

s-c=11.5

log(s-a)= .97772

log(s-b)=1.19033

log(s-c)=1.06070

--------

=3.22875

log s =1.56229

--------

2)1.66646

--------

log r =0.83323

now this part I'm having trouble with.

log r = 0.83323

log(s-a) = 0.97772

--------

log tan A/2 = 9.85551 - 10

A = ? << can you help me convert.

log r = 0.83323

log (s-b) = 1.19033

--------

log tan B/2 = 9.64290 - 10

B = ? same here my brain freezes

log r = 0.83323

log (s-c) = 1.06070

--------

log tan C/2 = 9.77253 - 10

C = ?

A+B+C= 180 deg 0' 2"