Answer
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Work Step by Step
The Law of Cosines gives
$c^2=a^2+b^2-2ab\ cosC$
In the case of a right triangle $C=90^\circ$, we have $cosC=0$ and the Law of Cosines becomes $c^2=a^2+b^2$, which is the Pythagorean Theorem. Thus, the Pythagorean Theorem is a special case of the Law of Cosines.
