Question

Use the Law of Cosines to find the values of x and y. (PLEASE HELPPP!!!!)

Answer 1

Answer:

$x = 49.8^\circ\\y = 54.6^\circ$

Step-by-step explanation:

Kindly refer to the image attached in the answer region for labeling of triangle.

AB = 16

BC = 19

AC = 15

$\angle ABC = x^\circ\\\angle ACB = y^\circ$

We have to find the angles x and y i.e. $\angle B \text{ and }\angle C$.

Formula for cosine rule:

$cos B = \dfrac{a^{2}+c^{2}-b^{2}}{2ac}$

Where  

a is the side opposite to $\angle A$,

b is the side opposite to $\angle B$  and

c is the side opposite to $\angle C$.

$\Rightarrow cos x = \dfrac{19^{2}+16^{2}-15^{2}}{2 \times 19 \times 16}\\\Rightarrow cos x = \dfrac{392}{608} \\\Rightarrow x = 49.8^\circ$

Similarly, for finding the value of y:

$cos C = \dfrac{a^{2}+b^{2}-c^{2}}{2ab}\\\Rightarrow cos y = \dfrac{19^{2}+15^{2}-16^{2}}{2 \times 19 \times 15}\\\Rightarrow cos y = \dfrac{330}{570}\\\Rightarrow y = 54.6^\circ$

Hence, the values are:

$x = 49.8^\circ\\y = 54.6^\circ$