Which equation correctly uses the law of cosines to solve for $y$ in a triangle with sides $x$, $y$, $z$ and angle $C$ opposite side $y$?

Given a right triangle with sides $a$, $b$, and hypotenuse $c$, which equation can be used to solve for $c$ using the Law of Cosines?

In triangle $MLN$, if side $MN$ is $20$ units, side $LN$ is $24$ units, and the included angle $\angle MLN$ is $60°$, what is the length of chord $ML$?

In triangle $BCD$, which is isosceles with $BC$ congruent to $BD$, what is the measure of angle $CBD$ if angle $C$ is $20°$? Choose the correct answer.

Given triangle $KNM$, which of the following statements about its sides is true?

Given triangle $GHF$ inscribed in circle $c$, with points $H$ and $F$ on the circle and side lengths $GH$ = $a$, $HF$ = $b$, and $FG$ = $c$, what is the length of line segment $GH$ in terms of $b$, $c$, and the included angle $A$ opposite $GH$?

Given a right triangle with legs of lengths $20$ and $21$, what is the length of the hypotenuse?

Which of the following sets of three numbers can represent the side lengths of an obtuse triangle?

In triangle $\mathrm{ABC}$, if side $\mathrm{AB}$ has length $b$, side $\mathrm{BC}$ has length $a$, and the angle at vertex $C$ is $\gamma$, what is the length of side $\mathrm{AC}$ according to the Law of Cosines?