### Angle Bisector of Triangle Dividing Opposite Side Into Proportionate Segments

Illustration to show that an angle bisector of a triangle divides the opposite side into segments which…

### Exterior Angle Bisector of Triangle Dividing Opposite Side Into Proportionate Segments

Illustration to show that a bisector of a an exterior angle of a triangle divides the opposite side…

### Parallel Lines Cut by Parallels, Corresponding Intercepts Proportional

Illustration to show that if parallel lines are cut by any number of parallels, the corresponding intercepts…

### Triangle Divided by Parallel Lines to Form Proportionate Triangles

Illustration to show that if a line is drawn through two sides of a triangle parallel to the third side,…

### Triangle Divided by Parallel Lines to Form Proportionate Triangles

Illustration to show that if a line divides two sides of a triangle proportionally, it is parallel to…

### 2 Right Pentagonal Pyramids

Illustration of 2 right pentagonal pyramids with hidden edges shown. The pentagonal bases are congruent,…

### 2 Right Rectangular Pyramids

Illustration of 2 right rectangular pyramids with hidden edges shown. The rectangular bases are congruent,…

### Similar Pentagonal Pyramids

Illustration of 2 similar right pentagonal pyramids with hidden edges shown. The height of the pyramid…

### Relation of Head to Height by Age

At birth the head measures about 4 times into height. At 5 years the head measures about 6 times into…

### Sector

The sector is a hinged rule with scales used for various mathematical calculations.

### Construction of Proportional Square

Illustration used to construct a square that shall be in proportion to a given square.

### Construction of Proportional Square

Illustration used to construct a square that shall be in proportion to a given square.

### Two Proportional Tetrahedrons

Diagram used to prove the theorem: "Two tetrahedrons having a trihedral angle in each equal, are to…

### Leaning Tower

Illustration of a leaning tower with a perpendicular drawn from the top of the tower to the ground to…

### Palm Tree Perpendicular to Ground

Illustration of a palm tree that is perpendicular to the ground. The tree is perfectly straight, as…

### Using Proportions To Find Heights of Trees

Triangle diagram for measuring heights of trees using proportions.

### Using Proportions To Find Heights of Trees

Triangle diagram for measuring heights of trees using proportions

### Inclined Plane Triangle

Inclined plane using right triangle and proportions

### Right Triangle Inscribed in Semicircle Shows Mean Proportional

Right triangle inscribed in semicircle. Illustration shows that the perpendicular from any point in…

### 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.

### Similar Triangles

Similar triangles with corresponding sides labeled.

### Similar Triangles

Similar triangles with corresponding sides labeled.

### Mutually Equiangular Similar Triangles

Illustration that shows two mutually equiangular triangles are similar.

### Similar Triangles With Respective Sides Parallel or Perpendicular

Illustration that shows that two triangles which have their sides respectively parallel, or respectively…

### Similar triangles

Illustration of 2 similar triangles with altitudes drawn.

### 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

### Similar Triangles for Height of Smokestack

Illustration of similar triangles used to find height of smokestack.

### Similar Triangles With Altitudes Drawn

Illustration that shows two similar triangles with altitudes drawn.

### Visual Angle

"Suppose the object a, appears to the naked eye of the length repreesnted in the drawing. Now, as the…