Remember the cosine function? This lesson will introduce the Law of Cosines, and demonstrate how to solve problems using aspects of the law. Use the images below to review the cosine function, especially if you have not focused on cosine recently.
You may have learned how to solve a cosine ratio problem in an earlier lesson. Work through the following problems as a review.
Problem 1
Problem 2
Problem 3
Find the cosine of angle K.
\(\mathsf{{cos(K) = }\frac{adjacent}{hypotenuse}}\)
\(\mathsf{{cos(K) = }\frac{9}{11}}\)
Find the cosine of angle A.
\(\mathsf{{cos(A) = }\frac{adjacent}{hypotenuse}}\)
\(\mathsf{{cos(A) = }\frac{28}{35}} { =} \frac{4}{5}\)
Find the cosine of angle C.
\(\mathsf{{cos(C) = }\frac{adjacent}{hypotenuse}}\)
\(\mathsf{{cos(C) = }\frac{21}{35}} { =} \frac{3}{5}\)
