Answer:
Y = 27.8°
Step-by-step explanation:
Apply the Law of Cosines which is given as c² = a² + b² - 2ab*Cos C
Where,
c = 8
a = 17
b = 16
C = Y
Plug in the values
8² = 17² + 16² - 2*17*16*Cos Y
64 = 545 - 544*Cos Y
64 - 545 = -544*Cos Y
-481 = -544*Cos Y
Divide both sides by -544
-481/-544 = Cos Y
0.884191176 = Cos Y
Y = cos^{-1}(0.884191176)
Y = 27.8478491° ≈ 27.8° (nearest tenth)
