2. Important Idea
•The Law of Cosines can
be used to solve oblique
triangles when SAS or SSS
information is given.
•The Law of Sines provides
a way to solve triangles
when the Law of Cosines
does not work.
9. Important Idea
The Greek astronomer,
Hipparchus of Nicaea, used
the idea in the last example
called triangulation to
estimate the distance from
the earth to the moon in 150
B.C.
14. Summary
The following is true about
the law of sines problems we
have worked:
•two angles are given
•the side opposite one of
these angles is given
15. Important Idea
When one angle and two
sides (with one side across
from the angle) are given, the
following may be true:
•No triangle exists
•one triangle exists
•two triangles exist