Strictly speaking, the sum of the angles on a triangle equals 180 degrees
A)in flat space.
B)on a spherical surface.
C)on a saddle-shaped surface.
D)all or any of the above
E)none of the above

Question

Quizplus · Accepted Answer

The sum of the angles on a triangle is a fundamental property of Euclidean geometry, which deals with flat space. This property does not hold on non-Euclidean geometries such as spherical or saddle-shaped surfaces, where the sum of the angles on a triangle can be more than or less than 180 degrees.

Strictly Speaking, the Sum of the Angles on a Triangle