12.07 cm
Explanation:
(1) We use the Law of Sines to find angle C
a / sin A = b / sin B = c / sin C
13.5 / Sin 81 = 8.2 / Sin C
13.67 = 8.2 / Sin C
Sin C = 8.2/13.67
C = Sin -1 0.5999
C = 37
(2)Then we find angle B
B = 180 – (37 + 81)
B = 62 degrees
(3)We use this angle and the Law of Sines to calculate side CA
13.67 = b / Sin 62
B = Sin 62 * 13.67
= 12.07 cm