Answer:
83.0°
Step-by-step explanation:
Given ∆XYZ, with 3 known sides, to find angle X, apply the Law of Cosines, c² = a² + b² - 2ab*cos(C).
For convenience sake, this formula can be rewritten to make the angle we are looking for the subject of the formula.
Thus, we would have this following:
[tex] cos(C) = \frac{a^2 + b^2 - c^2}{2ab} [/tex]
Where,
C = X = ?
a = 8 ft
b = 16 ft
c = 17 ft
Plug in the stated values into the formula and solve for X
[tex] cos(X) = \frac{8^2 + 16^2 - 17^2}{2*8*16} [/tex]
[tex] cos(X) = \frac{320 - 289}{256} [/tex]
[tex] cos(X) = \frac{31}{256} [/tex]
[tex] cos(X) = 0.1211 [/tex]
[tex] X = cos^{-1}(0.1211) [/tex]
[tex] X = 83.0 [/tex] (to nearest tenth)
