# The Sine Law question

Discussion in 'Geometry and Trigonometry' started by DropDeadFred, Nov 4, 2017.

1. Joined:
Nov 4, 2017
Messages:
1
0
So I'm working my way through a grade ten academic math course and I make it to the sine law section. Then I come across this equation in one of the examples and I honestly don't understand what was done to line one to result in line two. The problem is solving for e using the sine law, basically a/sinA = b/sinB = c/sinC. In the example this line is stated:

54.0/sin44 = e/sin50

Then the following line states:

e = 54.0 sin50/sin44

I don't understand what was done in line one to get to line two. To me, to isolate "e" you would multiply both sides by "sin50" and result in:

e = 54.0/sin44 X sin50

Please explain to me how this works 2. ### MathLover1

Joined:
Jun 27, 2021
Messages:
2,989
2,884
54.0/sin44 = e/sin50............cross multiply

54.0*sin50 = e*sin44........both sides divide by sin44
54.0*sin50/ sin44 = e*sin44/ sin44
54.0*sin50/ sin44 = e*1
54.0*sin50/ sin44= e

MathLover1, Jul 7, 2021
nycmathguy likes this.
3. ### nycmathguy

Joined:
Jun 27, 2021
Messages:
5,386
422
Great job as always.

nycmathguy, Jul 8, 2021
4. ### MathLover1

Joined:
Jun 27, 2021
Messages:
2,989
2,884
ty, I didn't know it was your post

MathLover1, Jul 8, 2021
nycmathguy likes this.
5. ### nycmathguy

Joined:
Jun 27, 2021
Messages:
5,386
422
It's not my post. I decided to thank you because DropDeadFred may not say thanks, which is very common here.

nycmathguy, Jul 8, 2021
MathLover1 likes this.
6. ### MathLover1

Joined:
Jun 27, 2021
Messages:
2,989
2,884
you know that person?

MathLover1, Jul 8, 2021
nycmathguy likes this.
7. Joined:
Jun 27, 2021
Messages:
5,386