Short answers, pulled from the story.
A press agent at WCAU-TV in Philadelphia coined the word simulcast in 1948. This portmanteau of simultaneous and broadcast described a new practice where radio and television networks aired identical programs at the exact same time.
Toscanini's NBC Symphony performance of the 15th of March 1952 stands as perhaps the first instance of radio and television simulcasting of a concert. Actual TV-AM radio simulcasts of the very same Voice of Firestone program began only on the 5th of September 1949.
The first such transmission in the United Kingdom occurred on the 14th of November 1972 when the BBC broadcast a live classical concert from the Royal Albert Hall on both BBC2 and Radio 3. The first pop rock simulcast followed almost two years later on the 27th of May 1974 with Van Morrison's London Rainbow Concert.
In the mid to late 1990s video game developer Nintendo utilized simulcasting to provide enhanced orchestral scoring for its Satellaview video games. Digital game data was broadcast to the Satellaview unit while partner satellite radio company St.GIGA simultaneously broadcast the musical portion via radio.
Al McCoy, Chick Hearn, Kevin Calabro and Rod Hundley were the last National Basketball Association team broadcasters to be simulcast. Until his retirement in 2016 Vin Scully's commentary for Los Angeles Dodgers home games was simulcast on radio and television for the first three innings.