ClipArt ETC
"If a sector revolves about its bounding radius as an axis, it generates what may be called a spherical cone."

Spherical Cone

"If a sector revolves about its bounding radius as an axis, it generates what may be called a spherical…

Illustration of a projection of a curved line.

Projection of a Curved Line

Illustration of a projection of a curved line.

The line ab is projected in the coordinate plane.

Length of a Line in Coordinate Plane

The line ab is projected in the coordinate plane.

The line ab is projected in the coordinate plane.

Length of a Line in Coordinate Plane

The line ab is projected in the coordinate plane.

The line revolved into V and projection H in coordinate plane.

Profile Line

The line revolved into V and projection H in coordinate plane.

Illustration of a line projection. If perpendiculars be drawn from the extremities of a line, as AB, to another line, as HK, as shown in the figure, that portion of HK included between the foot of each perpendicular is called the projection of AB upon HK.

Projection of a Line

Illustration of a line projection. If perpendiculars be drawn from the extremities of a line, as AB,…

Diagram used to prove the theorem: "The area of the surface generated by a straight line revolving about an axis in its plane is equal to the product of the projection of the line on the axis by the circumference whose radius is perpendicular erected at the middle point of the line and terminated by the axis."

Area of Surface Generated by a Straight Line

Diagram used to prove the theorem: "The area of the surface generated by a straight line revolving about…