Related Clues:

• 21st 92 Across letter
• 76ers, on scoreboards
• Greek symbol in the Golden Ratio
• Apt Greek letter for a Penn frat name
• Hard dividing an irrational number, which Diophantus once showed
• It’s three after 3-Down
• NBA Sixers, on scoreboards
• Greek letter 21
• Greek letter, or the first three letters of a Pennsylvania city
• Symbol of Euler's totient function
• Greek letter before chi
• Zeta ___ Beta
• Honor society starter
• Letter two after tau
• Ancient excerpt from Aristophanes