# How do you find #angleB# if in triangle ABC, #a = 15#, #b = 20# , and #angle A=30^@#?

##### 1 Answer

Dec 17, 2014

The answer is:

You have to use the law of sines, just as you thought. This law is:

We only need the first equation here, let's fill in the numbers.

We use cross-multiplication, then we find:

then by taking the inverse sine, we find