Answer:
320,000,000 * 0.638 = 204,160,000
Explanation:
Assuming the sample is a good representation of the people from the United States.
Since there were 1,000 surveyed... and 638 of them were wearing glasses, that makes a proportion of 638 out of 1,000 people, or 63,8 / 100 people... so 63.8%... or 0.638
So, if we assume that the US population is of 320 million, how many people does that make wearing glasses.... we just have to multiply 320M by 0.638