Bluebulb Projects' The Measure of Things presents:
9,900 is about one-fourth the number of Seats in Fenway Park
In other words, it's 0.267060 times the count of Seats in Fenway Park, and the count of Seats in Fenway Park is 3.74450 times that amount.
(2013 figures; daytime capacity) (a.k.a. The Cathedral of Boston) (Boston, Massachusetts)