Posted by **Amy** on Sunday, July 24, 2011 at 10:16pm.

Hi I'm reviewing the following solution in my trigonometry text book and I can't figure out how they got their answer. If someone can help explain how they calculated 542.25 for a^2 (nothing I do comes up with that number):

a2=b2+c2-2bcCosA

a2=(16)^2+(11)^2 -2(16)(11)Cos118

a2=542.25

|a2=|542.25

a=23.3

Thank you!

- Math -
**Reiny**, Sunday, July 24, 2011 at 11:14pm
I got exactly that.

a^2= 16^2 + 11^2 - 2(16)(11)cos118°

= 256 + 121 - 352(-.469471562)

= 377 **+** 165.2539898

= 542.253989

a = √542.2539898

= 23.2863

Are you following the order of operation?

- Math -
**Amy**, Monday, July 25, 2011 at 3:12pm
Thank you, I think it was how I was using my calculator. I didn't add brackets, now I got the same too. Very helpful to have that extra confirmation, I can't tell you how long I've been stuck on this question. Thanks a million!

## Answer This Question

## Related Questions

- Math - Rachel sent or received 10,290 text messages in the month of September. ...
- Help Chemistry - Can you please tell me if these are right? Determine the pH for...
- Math - Can someone explain this problem to me, I cannot figure out how they came...
- Trigonometry - Could someone please help me out with this? I've read my text ...
- Please Help CHEM - Can you please tell me if these are right? Determine the pH ...
- Math - 8*2sq+7*(4+1)= ? Can someone explain to me what to after the parenthesis...
- Math - I do not understand how to figure out my problem below and can not find ...
- English - Okay, another question on the Diary Of A Young Girl by Anne Frank. In ...
- Algebra - Rachel sent or received 10,290 text messages in the month of September...
- math practice help - add or subtract (2x^2+6x+1)+(-7x^2+2x-3) 5x^2-4x-2 -5x^2+8x...

More Related Questions