In non-right angled trigonometry, we can find an unknown side (in this case AC) using the Side Angle Side (SAS) rule when we are given two sides and an included angle (ie: an angle in between the two sides).
We use the Law of Cosine to find the unknown angle:
b^2 = a^2 + c^2 - 2ac cos B
{where b = AC, a = BC, c = AB, B = angle ABC}
We then substitute the values:
b^2 = 426^2 + 158^2 - 2(426)(158) cos 94
= 181,476 + 24,964 - 134,616 × cos 94
= 206,440 - (-9390.337)
= 206,440 + 9390.337
= 215,830.337 {3.s.f.}
Therefore:
b = _/215,83p.337 (square root of...)
= 464.575 {3.s.f.} (approximately)
So, AC = 464.575 {3.s.f.} (approx.)