Illustration used to show how to divide a given straight line into required number of equal parts.

Parallel lines are drawn by holding the triangle against the T-square at an angle, or another triangle,…

Perpendicular lines are drawn by fitting the hypothenuse of the triangle to the T-square at an angle,…

Illustration showing an angle of elevation from a horizontal line to a line of sight.

Diagram an ellipse with a tangent line that illustrates "A line through a point on the ellipse and bisecting…

Illustration used to show how to divide a given straight line into any number of equal parts.

Illustration used to show how to draw an equilateral triangle when given one side.

Illustration used to show how to draw an equilateral triangle when given the altitude.

"When a charge is moved from any point to another point in the same equipotential surface, no work is…

An exercise for mechanical drawing to construct a series of horizontal lines. The solid lines are drawn…

An exercise problem drawing a series of horizontal lines using a straight edge or triangle without using…

"A shaft-bearing secured to the floor, and used for running countershafts and lines when they cannot…

The illustration showing the centrifugal governor metal ball removed from the lathe to draw 180 degree…

Illustration of an axis of symmetry drawn with respect to a hexagon.

Illustration of an axis of symmetry drawn with respect to a hexagon.

Illustration of a horizontal line segment. A line segment is a section of a line with definite endpoints.

Illustration of a horizontal line segment. A line segment is a section of a line with definite endpoints.

Illustration of a horizontal line segment. A line segment is a section of a line with definite endpoints.…

Horizontal line can be drawn left to right by holding the pencil away from the point.

Diagram part of a hyperbola with a tangent line that illustrates "A line through a point on the hyperbola…

Illustration showing optical illusions. It is not always possible to trust the eye to be sure if the…

Illustration showing optical illusions. It is not always possible to trust the eye to be sure if the…

Illustration showing optical illusions. It is not always possible to trust the eye to be sure if the…

"Lines of force of a charged sphere and a conductor under induction. The negative electrification on…

"The magnetic poles of the earth do notc oincide with its geographical poles and, condequently, in some…

Isosceles Triangle with a dotted vertical line that is a line of symmetry.

Letter A with a dotted vertical line that is a line of symmetry.

Letter B with a dotted horizontal line that is a line of symmetry.

To find the angle between two given lines a, b of which the projections a1, b1 and a2, b2 are given.

Illustration used to show how to find a straight line of the same length as a given arc of a circle.

Illustration showing a line with a midpoint drawn from a given exterior point to a given circumference.

Illustration showing a line that remains parallel to a given line, and touches at one end a given circumference.

Illustration showing a line that moves so that its ends constantly touch two fixed lines which are perpendicular…

Illustration showing that the perpendicular is the shortest line that can be drawn to a straight line…

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

Projections of a line inclined to both the horizontal and vertical planes will not show its true length,…