🔍 Key Concepts

• Planes through the Earth's center and how they intersect a sphere • Difference between great circles and small circles • Relationship of equator and meridians to great circles

💭 Think About

• When a flat plane passes through the exact center of a sphere, what kind of circle is formed on the surface? • Are the equator and meridians special examples of a more general type of circle on the Earth, or are they the only ones? • What happens if the plane does NOT pass through the Earth’s center—what type of circle would that be?

✅ Before You Answer

• Be clear on the definition of a great circle versus a small circle • Check which options are specific named lines (like equator or meridian) versus general geometric concepts • Confirm whether any angle through the center still shares the same geometric property on a sphere