Final answer:
Most of South America lies between the lines of longitude of approximately 35W and 80W, establishing its position in the Western Hemisphere.
Step-by-step explanation:
Most of South America lies between the lines of longitude of approximately 35 degrees West (35°W) and 80 degrees West (80°W). These lines of longitude, also known as meridians, help us identify the specific position of the continent of the Western Hemisphere. The prime meridian, which is set at 0 degrees longitude, is a reference point from which these measurements are made. To the west of the prime meridian, the degrees increase until reaching the International Date Line, which is approximately at 180 degrees longitude.
The eastern boundary of South America, which includes countries such as Brazil, is closer to the 35°W line, while the western part, including countries such as Peru and Chile, extends towards 80°W. It's important to remember that longitude lines are measured both east and west from the prime meridian. They play an essential role in navigation and geography by helping us locate places on Earth's surface.