5. Trigonometry

Law Of Cosines — Quiz

Test your understanding of law of cosines with 5 practice questions.

Practice Questions

Question 1

In $\triangle ABC$, if $a = 5$, $b = 7$, and $C = 60^\circ$, what is the length of side $c$?

Question 2

A triangle has sides of length $x = 8$, $y = 10$, and $z = 12$. What is the cosine of the angle opposite side $z$?

Question 3

In $\triangle PQR$, if $p = 6$, $q = 8$, and $r = 10$, which angle is the largest?

Question 4

Two sides of a triangle are $4$ cm and $6$ cm, and the angle between them is $120^\circ$. What is the length of the third side?

Question 5

If a triangle has sides $a = 3$, $b = 4$, and $c = 5$, what is the measure of the angle opposite side $c$?