How do i know when to use inverse law of cosine instead of law of cosine or are they the same?

Step-by-step explanation:

There is no such thing as the inverse Law of Cosines.  You CAN use the law to find a missing angle, which is found by finding the inverse cos of a ratio.  For example, if you have all 3 sides of a non-right triangle and you are looking for the measure of an angle, you would do all the required math, and in the end you would have that cos(x) = some fraction.  Take the inverse cos on your calculator of this fraction and get the angle value.

In other words, the Law of cosines can be used to find both a missing side OR a missing angle.

to find the unit price, we must figure out the cost of one item (in this case one dish towel).   to do this, we divide the total price ($7.92) by the number of items bought (for this problem it is 8, because there are eight dish towels in one pack).  

$7.92/8 = $0.99

therefore, the unit price, or the price of one dish towel, is $0.99.

hope this !

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