A sphere with arcs and poles. "The distance of all points in the circumference of a circle of a sphere…
"Every section of a sphere made by a plane is a circle."
Illustration of a sphere generated by the revolution of a semicircle ACB about its diameter AB as an…
Illustration of a sphere with a tangent plane. "A plane perpendicular to a radius at its extremity is…
Illustration of a sphere with a tangent plane. "A plane perpendicular to a radius at its extremity is…
Illustration of a sphere with a polyhedral angle whose vertex is at the center of the sphere and whose…
A sphere with quadrants and poles. "A point on the surface of a sphere, which is at the distance of…
Illustration of equal spheres with equilateral and equiangular triangles.
Illustration of two intersecting spheres. "The intersection of two spherical surfaces is the circumference…