Patrick Ewing, Georgetown's sophomore all-America basketball center, was one of 12 players selected yesterday to play in the Pan American Games in Venezuela this summer.

The Atlantic Coast Conference placed three players on the team, including first-team all-Americas Michael Jordan and Sam Perkins of North Carolina. Mark Price, ACC rookie-of-the-year from Georgia Tech, joined Waymon Tisdale of Oklahoma as the only freshmen selected.

The other seven players are Michael Cage of San Diego State, Jim Master of Kentucky, Charlie Sitton of Oregon State, Leon Wood of Cal State-Fullerton, Chris Mullin of St. John's, Greg Stokes of Iowa and Fred Reynolds of Texas-El Paso.

Adrian Branch of Maryland, Billy Martin and Mike Jackson of Georgetown were among the players who tried out but were not selected . . .

Cheryl Thompson, girls' basketball coach at W.T. Woodson High School in Fairfax, has been named coach of the women's team at Georgetown U. Her Woodson team this year (27-1) won the Virginia AAA state championship. Thompson was named the metropolitan area's coach of the year by The Washington Post. She is a native of Oriental, N.C., and graduated from East Carolina in 1972.