Final answer:
Johannesburg in the 1940s can be described as burgeoning, industrial, and diverse, owing to its mining boom and resultant population growth and cultural diversity.
Step-by-step explanation:
Three adjectives to describe Johannesburg in the 1940s are burgeoning, industrial, and diverse.
During this period, Johannesburg experienced significant growth due to its booming mining industry, which contributed to South Africa's national wealth.
The city's industry attracted a multitude of job seekers which made it a melting pot of various cultural backgrounds.