Length BC is opposite of angle A and AC is opposite of angle B.
<span>Since we know one set of opposite angles and lengths and looking for the length where we know the opposite angle, we can use law of sines: </span>
<span>a / sin(A) = b / sin(B) </span> <span>8 / sin(71) = b / sin(42) </span> <span>b sin(71) = 8 sin(42) </span> <span>b = 8 sin(42) / sin(71) </span> <span>b ≈ 5.66 units (rounded to 2DP)</span>