Answer: 73.39845
Explanation:
Since this is not a right triangle, we can't use the Pythagorean theorem and must use a different method. Since all sides are known, we can use the cosine rule to find the angle QPR
[tex]cos(x) =\frac{Q^{2}+R^{2}-P^{2} }{2QR}[/tex]
the sides P, R, and Q refer to the side that is opposite to that angle (see picture below)
so P = 9, R = 7, Q = 8
plug these values in
[tex]cos(x) =\frac{7^{2}+8^{2}-9^{2} }{2*7*8}[/tex]
[tex]cos(x) =\frac{7^{2}+8^{2}-9^{2} }{2*7*8}[/tex]
[tex]cos(x)=\frac{32}{112} = \frac{2}{7}[/tex]
use calculator to solve for x
x = 73.39845
