The blob from outer space has been found. It is spherical, and its diameter is the sinusoidal function of time. At 2:00 AM, you seen the blob's diameter to be at its maximum, 3.2 meters. Diameter then shrinks, reaching its minimum, 1.4 meters, at 7:00 AM. Determine the second time after 7:00 AM that blob's diameter is 1.8 meters?