Answer:
152.53°
Step-by-step explanation:
The Law of Cosines is useful for finding an angle when sides are given.
a^2 = b^2 +c^2 -2bc·cos(A)
A = arccos((b^2 +c^2 -a^2)/(2bc))
A = arccos((18^2 +17^2 -34^2)/(2(18)(17))) = arccos(-543/612)
A ≈ 152.53°
