You have to use the Law of Cosines here, since there's no other way to solve this. it's not a right triangle, so you can't use the Pythagorean Theorem. The Law of Cosines will help us find the missing side length then we will have to use the Law of Sines to find another angle. Then after that we will use the Triangle Angle-Sum theorem to finish it off. Ready? The Law of Cosines to find side b is
and fill in the info we know, which is everything but the b. 
. Doing all that math gives us that side b = 40.9 or 41. Now the Law of Sines to find missing angle A or C. Let's find A. 
. That gives us that angle A is 29. Now use the fact that all triangles add up to 180 to get that angle C is 42. And you're done!
Classifying triangles
2 answers:
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Answer: Second option.
Step-by-step explanation:
You need to use the following formula:
Where "B" is the area of its base and "h" is the height.
According to the data given in the exercise, you know that:
Therefore, knowing this values, you can substitute them into the formula shown before and then evaluate, in order to calculate the volume of thi right pyramid whose base is a regular hexagon.
Then, you get: