The Law of Cosines
The Law of Cosines – Example 2: \(b=20, a=8, c=14\) \(cos B= \frac {14^2+8^2-20^2}{2(14)(8)} =\frac {196+ 64 – 400}{176}=\frac{-140}{224}=-0.625\) Since \(cosB\) is negative, \(B\) is an obtuse angle. \(B≅128.69 ^\circ \) Exercises for the Law of Cosines In the ABC triangle, find the side of c. 1. 2. 3. \(\color{blue}{31.12}\) \(\color{blue}{44.68}\) \(\color{blue}{21.49}\)
8 Useful Tips on Learning Mathematics Effectively
Being able to apply algebraic arithmetic correctly, as well as knowing the basic geometric rules is necessary not only to pass exams well and enter a good college or university. For additional educational resources,. Mathematics is needed to study many other subjects. For example, physics, economics, chemistry, and even biology. We also apply math almost […]
