In Euclidean geometry, the sum of the interior angles of a triangle is always 180°. However, in spherical geometry, the sum of the interior angles of a triangle is always greater than 180°. This occurs because triangles are drawn on the surface of a sphere, where the curvature of the surface affects the angles.

Now, let's analyze the given options:

• A. 30°, 60°, 90° → Sum = 180° (belongs to Euclidean geometry, not spherical)
• B. 35°, 60°, 80° → Sum = 175° (belongs to neither Euclidean nor spherical geometry)
• C. 20°, 60°, 100° → Sum = 180° (belongs to Euclidean geometry, not spherical)
• D. 65°, 60°, 60° → Sum = 185° (greater than 180°, belongs to spherical geometry)

Thus, D. 65°, 60°, 60° belongs to spherical geometry.

Would you like further clarification on this concept or on spherical geometry in general?

Here are five related questions:

1. How is the sum of the interior angles of a triangle calculated in spherical geometry?
2. What real-world applications use spherical geometry?
3. How does curvature affect the properties of triangles in spherical geometry?
4. Can a triangle in spherical geometry have angles less than 180°?
5. What is the significance of "geodesics" in spherical geometry?

Tip: In spherical geometry, the larger the area of the triangle on the sphere, the larger the sum of its angles!