Question

QUESTION 1: Marques made a mistake when solving this problem. On what line did he make the error?

Answer 1

Line 2 presents the error for the solution presented because the square of numbers: 14 and 8 was calculated incorrectly.

Law Cosines

This law can be applied when two sides of the triangle and the angle formed for these sides are known. Therefore, from the law of cosines, it is possible to write the relation between sides and their respective cosines. See below:

                           $c^2=a^2+b^2-2*a*b*cos(C)$

For solving this question, you should apply the Law Cosines and after that compare your solution with this exercise. From the comparison, you should identify the mistake for the solution presented in this problem.

• Applying Law Cosines

                 $c^2=a^2+b^2-2*a*b*cos(C)\\ \\ c^2=14^2+8^2-2*14*8*cos(80)\\ \\ c^2=196+64-224*0.1736\\ \\ c^2=196+64-38.8864\\ \\ c^2=221.1136\\ \\ c=\sqrt{221.1136}=14.9$

• Comparison and identification of the mistake

He made the error in line 2. Instead of calculating the square of 14 and 8, he multiplied these numbers by 2. This was the error.

Read more about the law cosines here:

brainly.com/question/7872492