 ### Reference Angles/Triangles Formed by Angles in Quadrants With Labels

Lines drawn to horizontal to form triangle ratios (reference triangles, angles). Axes, quadrants, abscissa,… ### Circle With 36 degree Angles and Radius 1.5 in.

Circle with 36 degree angles marked. This diagram can be used with the following trig problem: Locate… ### Circle With Center o and Radius r with point P

Circle modeling the earth. O is the center of the earth, r the radius of the earth, and h the height… ### Circle With a Chord of 2 ft. and a Radius of 3 ft.

Circle with chord AB=2 ft. and radius OA = 3 ft.. Triangle AOC is a right triangle. Angle AOC=half angle… ### Curve in Pavement of Road

Illustration of blueprint used by highway engineers to widen the pavement on the inside of the curve… ### Point Distance

To determine the distance between two points A, B given by their projections. ### Military Distance Measurement

An illustration of military personnel measuring distance. ### Light Intensity

"The radiation of light, or the intensity of light is inversely proportional to the square of the distance… ### Light Intensity Versus Distance

"Another illustration of how luminous density varies inversely as the square of the distance." —Croft… ### Light Intensity at Different Distances

"A card placed at point A receives normal light. At point B the card receives four times as much light,… ### Single Microscope

"Let a be the distance at which an object can be see distinctly, and b, the distance at which the same… ### Planet Distance

"Relative distance of the Planets. Having now given a short account of each planet composing the solar… ### Path of Projectile

Illustration modeling the path of a projectile. ### Roof With 30 degree Inclination for Trigonometry Triangle Problems

Roof with a slope of 30 degrees. Angle theta is the inclination to the horizontal of the line AB, drawn… ### Sliding Contact

These are skew bevel wheels, made of a hyperboloid of revolution around an axis. ### Square

An illustration of a square and triangles within the square. This is an example of a problem that can… ### Two Squares With Sides of Lengths 3,4,5 Placed at Right Angles to Each Other

Two set squares, whose sides are 3,4, and 5 in., are placed so that their 4-in. sides and right angles… ### Surveying

A team of surveyors in the country. ### Oblique Triangle for Distance Across a River

Illustration of oblique triangle used to find distance across a river. ### Oblique Triangle for Distance Across a River

Illustration of oblique triangle used to find distance across a river. ### Oblique Triangle for Distance Across Lake

Illustration of oblique triangle used to find distance across a lake. ### Inclined Plane Forming Right Triangle

Inclined plane forming right triangle showing the velocity of a body sliding a distance,s, down a smooth… ### Similar Triangles for Distance Across Lake

Illustration of similar triangles used to find distance across a lake. ### Similar Triangles for Distance Across Stream

Illustration of similar triangles used to find distance across a stream ### Wedge

"The wedge is a movable inclined plane, and is used for moving a great weight a short distance. A common…