**Topic--Law of Sines Investigated
with GSP 4.0**

__The basics__:

1. **Law
of Sines overview**: Click here for introductory material
related to the law of sines.

2. **Law
of Sines--ambiguous case**: In the past, some of my biggest
headaches in teaching (for both me and my students, I'm sure)
have been related to the ambiguous case of the law of sines. Click
on this link to see a GSP 4.0 demonstration that aids the discussion
of this topic.

3. **Law
of Sines--proof #1**: Try deriving the law of sines yourself.
(Hints and suggestions are provided, as well as a complete proof
if you give up.)

4. **Law
of Sines--proof #2:** This proof of the law of sines points
out a relationship between a triangle and its circumcircle.

5. **Can
the law of sines be used if...?**

Extensions--Further proofs/problems related to the law of sines:

1. **How is the area of a triangle related
to the circumcircle of that triangle?**

2. **For
any triangle ABC, b(cosC) + c(cosB) = ???**

3. **In
any triangle ABC, a(sinB - sinC) + b(sinC - sinA) + c(sinA - sinB)
= ???**