Short answers, pulled from the story.
The LP record is a 12-inch disc made of black vinyl copolymer that spins at 33 revolutions per minute. Columbia Records introduced this format in 1948 as a direct response to the limitations of existing media.
Each side of a standard 12-inch LP could play for about 25 minutes allowing for a total runtime of approximately 50 minutes. This replaced the abrasive shellac compound which limited playing time to less than five minutes per side for a standard 12-inch diameter record.
CBS Laboratories head research scientist Peter Goldmark led Columbia's team to develop a phonograph record that would hold at least 20 minutes per side. Columbia Records unveiled the LP at a press conference in the Waldorf Astoria on the 21st of June 1948.
By 1983 cassettes were outselling LPs in the US after audio quality improvements via better tape formulations. The Compact Disc introduced in 1982 offered theoretically almost noiseless recording unaffected by repeated playing or slight scuffs.
In 2022 US vinyl sales reached 41 million units surpassing sales of the Compact Disc for the first time since 1987. This made the LP the highest selling physical format again within the United States market.