The earth is about 150 million kilometers from the sun. the orbit around the sun is not a perfect circle, but is approximately a circle. if the orbit of the earth around the sun were circular, what would be the equation if the origin of the coordinate system were placed at the sun? x² + y² = (150,000,000)² x² - y² = (150,000,000)² x²y² = (150,000,000)²