The Size of a Supermassive Black Hole

The goal of this exercise is to estimate the size (radius) of a supermassive black hole (active galactic nuclei) using imagery, a light curve, and Kepler's third law.  It is part of a collection of short lecture-tutorial (or homework) activities, designed to be both quantitative and accessible to the introductory astronomy student. Each of which involves interpreting some real data, solving a problem using ratios and proportionalities, and making a conclusion based on the calculation.