Question

Which of the following problem types can always be solved using the law of cosines or sines? Check all that apply.

Please explain. Thank you!

Answer 1

AAA doesn't work for either sin or cos, because you will need at least 1 side length for sin and at least 2 side lengths for cos to be able to solve. (Remember that in an equation you can only solve if you can get it down to 1 variable)

Answer 2

For SAA, that gives you one side and angle that are opposite from each other and one other piece of info. Use sin in that general case.

Answer 3

For SAS, you know 2 sides and the angle opposite the other side, that gives you enough info to use cos and you can solve for the third side.

Answer 4

For SSS, always use cos.

Answer 5

For SSA, you have an angle and a side opposite from each other and another piece of info, so use sin.

Answer 6

Can you try ASA? What do you think?

Answer 7

ASA is when we know two angles and a side between the angles. So we use the law of sines. Is this right?

Answer 8

Well, for sin, we need to know about a side and an angle opposite that side, with one other piece of info. Do we have a side and its opposite angle?

Answer 9

I guess not.

Answer 10

Right, it may help to draw it. Do you know what I mean by a side and its opposite angle?

Answer 11

Yes I think I got it.

Answer 12

:) Ok, sweet.

Answer 13

@JoannaBlackwelder So for this problem the answers are only SAA, SAS, SSS and SSA?

Answer 14

Thank you very much for your time and help! @JoannaBlackwelder

Answer 15

Yep, you are very welcome! :)