Illustration showing the intersection of a plane with an octagonal prism.

Diagram of a cone intersected by plane J to form a parabola. Also pictured is a circle formed by the…

Diagram showing how to construct a parabola when given the directrix (d), the focus (F) and the eccentricity…

A pusher aeroplane plan illustrating the proper ribbing and wiring for the plane. The wires are used…

A propeller airplane plan illustrating the proper location of the skeleton and placement of the wires…

A top view plan of a propeller aeroplane, or airplane. The plan shows the proper ribs and skeleton for…

A side view plan of a propeller aeroplane for two people. The plan illustrates the the proper location…

A plan for pusher aeroplane, or airplanes. The propeller of the pusher plane is located behind the cockpit…

"If a straight line is perpendicular to each of two straight lines at their point of intersection it…

"If one of two parallels is perpendicular to a plane, the other is also."

"The locus of a point in space equidistant from the extremities of a straight line is the plane perpendicular…

If a straight line is perpendicular to each of two other straight lines in a plane at their point of…

Straight line AB is perpendicular to the lines in plane MN at point B. "If from the foot of a perpendicular…

Two straight lines, AB and CD, perpendicular to the same plane (MN) are parallel.

Two intersecting planes on a third plane. "If two intersecting planes are each perpendicular to a third…

Illustration of two parallel planes. "Two planes perpendicular to the same straight line are parallel."

Two parallel planes perpendicular to a line (AB). "A straight line perpendicular to one of two parallel…

Illustration of a prism - a polyhedron of which two faces are equal polygons in parallel planes, and…

"A series of planes as S—S are passed perpendicular to the axis of revolution, cutting out the…

A propeller airplane with rudder, elevator, and ailerons. The rudder stabilizes the plane vertical,…

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 the intersection of a square pyramid and a plane.

Illustration of the intersection of a square pyramid and a plane.

Inclined plane forming right triangle showing the velocity of a body sliding a distance,s, down a smooth…

Illustration of the intersection of a triangular pyramid and a plane.