Answer:
Y ≈ 27.8°
Step-by-step explanation:
Use (a, b, c, C) = (x, z, y, Y) and fill in the given formula.
y² = x² +z² -2xz·cos(Y)
2xz·cos(Y) = x² +z² -y²
cos(Y) = (x² +z² -y²)/(2xz) = (17² +16² -8²)/(2·17·16) = 481/544
Y = arccos(481/544) ≈ 27.848°
Y ≈ 27.8°
