Re: Can some explain why?

Do you mean the angle A=120°?

Re: Can some explain why?

yes 90 degrees + 30 degrees = 120 degrees. If this is less than 180 degrees, ( as was explained to me) this indicates that another triangle solution could be found.

Re: Can some explain why?

But if A=120° then you don't have a right-angle triangle anymore and so the Law of the sines doesn't work. Wat would be the measure of the other angles in a triangle with A=120° along you?

EDIT: Forget this post, I'm from Belgium so I didn't realise what the 'Law of the Sines' is. Now I do, so this post doesn't make sense.

Re: Can some explain why?

The original problem is this: a=4, b=8 and A=30 degrees.

which gives a 90 degree right triangle.

When you use the Law of Sines to get an Angle, there is a possibility that there are multiple triangles that the above measurements can be part of. Our professor told us that the way to determine if there are multiple triangles was to do this: Lets say you are solving for angle B.

with algebra:

arcsin(1) = 90 degrees.

ok so now, we know that the angle of B is 90. But how to determine if there are any other triangles? The formula is:

y = (180-B) + A. If y is less than 180, there is another possible triangle.

So since we've determined that B is 90 degrees:

(180-90)+30 = 120. 120 < 180.

However, the book states that there is only 1 triangle possible for a 90 degree right triangle. What I want to know is why?

Re: Can some explain why?

Re: Can some explain why?

Yes I realized I typoed part of it. I'm really having a hard time getting latex right, and I tend to screw up the problem trying to get it to look right. It is correct now.

Re: Can some explain why?

Indeed B=90° and with A given that implicates C=60°. If A is given then there's just one possibility for B and C.

In the formula you gave what is y?

Re: Can some explain why?

y is just a variable that the professor made up to hold the result of the formula (180-B) + A