Question

Pre-calculus question!
if < A=80°, < B=20°, b=12cm then find a???
Side a=________
Can anyone shed some light??This is my last hw question and I don't really know how I would find angle a D: Im sure this is a brainer, but could anyone help? :O Please and thank you!

Answer 1

remember the sine rule?
\[{\sin A\over a}={\sin B\over b}\]
when you have an angle and side opposite to it given to ya, check if you can use the sine rule

Answer 2

kapeesh?

Answer 3

so,
a=\[\frac{ sinB }{ b(\sin(A)) }\]
=\[\frac{ \sin(20) }{ 12(\sin(80)) }\]
=.029 ???
:O

Answer 4

your re-arrangement of the terms is wrong. try again with the first step

Answer 5

hmm... ok,
a=\[\frac{ \sin(20) }{ \sin(80) }*(12)??\]
=4.17 ?? D:

Answer 6

nope

Answer 7

why not go step by step? there is no rush. take it slow man.
\[
{\sin(80^\circ)\over a}={\sin(20^\circ)\over 12}
\]

Answer 8

ok, I think this is it lol and yea I'm kind of rushing, and not thinking I'm about to go visit family soon and I want to get as much of this done as possible ^^;

a=\[\frac{ b }{ sinB }*(sinA)?\]

Answer 9

I'm about to leave now. I'll be back in the evening and I will see your response then!! Thanks for all your time!

Answer 10

yes. that is correct.