Women have been named principals of three Montgomery County high schools, bringing the number of women in those posts to four.

Out of 22 county high schools only two now are headed by women, one of whom is retiring. There currently are three vacancies in the county.

While women make up the majority of the ranks of public school teachers, they do not dominate the top-ranking jobs.

"Needless to say, we're very pleased" about the appointments, said Jane Dofflemeyer, president of the county's 300-member chapter of Women in Education. "But the organization feels that the whole school system has an obligation to look at the way it has historically treated women."

More than 70 percent of the teachers in Montgomery County are female, but men hold disproportionately higher positions, according to school board records. Men head 63 out of 106 elementary schools; in addition, 38 out of 49 assistant senior high principals in the county are men.

One out of three associate superintendents--the highest ranking position next to superintendent--is female, as is one of the three associate area superintendents.

"We've got a way to go," observed Connie Mitchell, treasurer of Women in Education and a statistician in the testing department.

The three new high school principals are:

* Marion Bell, principal at Francis Scott Key Junior High in Silver Spring, who will be the county's only black female high school principal when she moves to Seneca Valley in Germantown to replace retiring principal Nathan Pearson.

Bell, a graduate of Bennett College in Greensboro, N.C., came to the county in 1972 as a guidance counselor.

* Diane Ippolito, principal of Montgomery Village Junior High in Gaithersburg, who will succeed Anita J. Willens at Woodward High in Rockville.

Ippolito, a graduate of Trinity College in Washington, started as a teacher in the county in 1968.

* Nancy Powell, principal at Redland Middle School in Rockville, who will move to Magruder High in Rockville. Powell will replace retiring principal Mark Nejako.

Powell, a graduate of Wellesley College in Massachusetts, came to the county in 1960 as a teacher at Springbrook.