TTie engagement and approaching marriage of MissKathy Louise Zirlax to Mr. Donald C. McKay of Austin Ls announced by her parents Mr. and Mrs. Donald B. Zirlax. He ls the son of Mr. and Mrs. Charles A. McKay of Dallas. Miss Zirlax Is a 1070 graduate of Mason High School and attended Ai^elo State University. Her fiance Is a graduate of Crane High School a«l of Angelo State University in December of 1972. The wedding is planned for April 7 in The First United Methodist Church.