Answer: $400 million

An index of 1.8 means that quarter 1 sales are 80% above the norm (average). Thus, each quarter has average sales worth $\frac{\$180,000,000}{1.8} = \$100,000,000$. Therefore, the annual estimate = 4 * Quarter average = 4 * \$100,000,000 = \$400,000,000.

Author: Tanishq Prabhu