The real estate assets - involved 30 of the Dance Real Estate Investment Corp. - 30 investment properties worth an estimated $46 million - are being acquired by Equitable Life Assurance Society of America of New York City.

Jerold E. Williamson, president of Danac, said in response to questions that transaction is being made on the basis of one share of stock in Danac - but that share of stock will mean ownership of the 30 properties. They include Gaithersburg Square Shopping Center and the Quince Orchard Plaza (shopping center) and office building.

All of the properties were built and developed by Danac in the 14 years since it was founded as a publicly owned corporation by Dermott A. Nee, a furniture company executive.

Some years ago the assets of Danac were acquired by the Richmond Co., a Virginia financial holding company, which itself was acquired recently by the Continetal Group of New York City.

Williamson said the sale of the package of real properties was made because it is not now financially worth-while for a public corporation to own real estate as a source of earnings for stockholders. He added that Danac will continue to perform a role in development, management and leasing of real estate as income-producing activities. Danac still owns 180 acres of Montgomery County land in various parcels worth an estimated $10 million.

The Bethesda-based Danac firm developed a number of its investment properties on the I-270 corridor in Montgomery County. One of those properties, Williamson said, is the new -headquarters site of the Joseph R. Harris women's wear firm.