BEAVERTON, Ore. — Nike Inc. reported U.S. apparel sales slumped 20 percent to $85.1 million in the third quarter ended Feb. 28, while international apparel sales slid 7.4 percent to $56.6 million Nike’s net earnings in the quarter skidded 29.3 percent to $63.2 million, or 85 cents a share, from $89.5 million, or $1.16, a year earlier.

Total sales dipped 10.3 percent to $871.8 million from $972 million.

In the nine months, earnings fell 20.2 percent to $229.6 million, or $3.03 a share, from $288.1 million ,or $3.74, a year earlier. Sales slipped 5.5 percent to $2.78 billion from $2.95 billion.

Apparel sales in the U.S. in the nine months fell 8.4 percent to $261.6 million, while international apparel sales slid 6.5 percent to $226.2 million.

Philip H. Knight, chairman, said results were in line with expectations. Knight said that while worldwide orders scheduled for delivery between March and July 1994 were 3 percent below year-ago levels, orders for the first quarter of fiscal 1995 increased 4 percent, marking the first time in over a year Nike has seen positive futures trends.

“We hope to see those trends strengthen in the months ahead,” Knight said.