Read this: Founded at various times in the university's history, the professional schools originally were scattered throughout Chicago. In connection with a 1917 master plan for a central Chicago campus and President Walter Dill Scott's capital campaign, 8.5 acres (3.44 ha) of land were purchased at the corner of Chicago Avenue and Lake Shore Drive for $1.5 million in 1920. The architect James Gamble Rogers was commissioned to create a master plan for the principal buildings on the new campus which he designed in collegiate gothic style. In 1923, Mrs. Montgomery Ward donated $8 million to the campaign to finance the construction of the Montgomery Ward Memorial Building which would house the medical and dental schools and to create endowments for faculty chairs, research grants, scholarships, and building maintenance. The building would become the first university skyscraper in the United States. In addition to the Ward Building, Rogers designed Wieboldt Hall to house facilities for the School of Commerce and Levy Mayer Hall to house the School of Law. The new campus comprising these three new buildings was dedicated during a two-day ceremony in June 1927. The Chicago campus continued to expand with the addition of Thorne Hall in 1931 and Abbott Hall in 1939. In October 2013, Northwestern began the demolition of the architecturally significant Prentice Women's Hospital. Eric G. Neilson, dean of the medical school, penned an op-ed that equated retaining the building with loss of life.

In 1920, how many acres were purchased for $10 million for a new central Chicago campus?
What is the answer? (If it cannot be answered, return "unanswerable")
unanswerable