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Laws
of
Sines
and
The law
of
sines
and law of
Gosines
cosines
apply
to all
triangles:
Law
of
sines:
a:b:c
sin
A
sin
B
sin
C
Use
when you know:
I
One side, two
angles.
t
TWo
sides,
angle opposite
a
known
side.
Law
of
cosines:
a2:62 + c2
2bc
cosA
Use
when you know:
I
r
TWo
sides,
angle
between
them.
I
Three
sides.
Example: Law of Sines.
You
look down
from the top of
a
5000-foot
mountain
with
your
telescope
and
see
two
large
water towers,
one
behind the
other.
When you
point the
telescope
at
one towe{,
the
an-
gle from horizontal is 33o. For the other towe{, the angle from
horizontal is 48o.
How
far apart are the
towers?
\<-
Side c
r60
9: Additional Eramples
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