Read this sentence from the article. Rudolph was already a known quantity in the world of track.
What does the idiom “a known quantity” mean in the sentence above?

a known quantity means, someone or something whose abilities or characteristics are well known. When she was cast in the role of the princess, she was already a known quantity from her work in several films.

so basically Rudolph was known for something either about the character or something the character does. I hope this helps! :)

the president was the speaker and it was a great part of history.

explanation:

video of the national aeronautic space administration's (nasa) coverage of president john f. kennedy’s address at rice university, houston, texas, concerning the nation's efforts in space exploration. in his speech the president discusses the necessity for the united states to become an international leader in space exploration and famously states, "we choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard."

men had a stronger claim to titles and wealth during the renaissance.