A rainstorm lasts for 6.3 hours, building from a drizzle to a heavy rain, then dropping back to a drizzle. The rate, r, of the rain (in inches per hour) is given by
r = 0.2t; 0 < t < 4.5
r = 3.15 - 0.5t; 4.5 < t < 6.3
where t is the time in hours. What is the total rainfall?