Answer:
35 cm
Explanation:
You can use the Cosine Rule to find the length of a side when two sides and the included angle are given.
a² = b² + c² - 2bc cos A
a² = (36²) + (52²) - 2(36)(52) cos 42°
a² = (1296) + (2704) - (3744)(0.7431448255)
a² = (4000) - (2782)
a² = 1218
a = ✓1218
a = 34.9 cm