Explanation:
first : the sum of all angles in a triangle is always 180°.
second : the law of sine
a/sin(A) = b/sin(B) = c/sin(C)
a, b, c are the sides, A, B, C are the the corresponding opposite angles.
therefore,
angle J = 180 - 71 - 46 = 63°
j/sin(J) = k/sin(K)
11/sin(63) = k/sin(46)
k = 11×sin(46)/sin(63) = 8.880673249... m