Regular pentagon inscribed in a circle, circumscribed about a circle.
Illustration of a plane parallel to the base passing through a cone (section made is a circle).
Illustration of a plane parallel to the base passing through a cone (section made is a circle).
Illustration of a sphere generated by the revolution of a semicircle ACB about its diameter AB as an…
"Every section of a sphere made by a plane is a circle."
A sphere with arcs and poles. "The distance of all points in the circumference of a circle of a sphere…
A sphere with quadrants and poles. "A point on the surface of a sphere, which is at the distance of…
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 two intersecting spheres. "The intersection of two spherical surfaces is the circumference…
Illustration of a sphere with a polyhedral angle whose vertex is at the center of the sphere and whose…
Illustration of equal spheres with equilateral and equiangular triangles.
Illustration of half of an ellipse. "The ordinates of two corresponding points in an ellipse and its…
Illustration of half of an ellipse and its auxiliary circle used to construct an ellipse by points,…
Illustration of half of an ellipse. The square of the ordinate of a point in an ellipse is to the product…
Illustration showing the tangents drawn at two corresponding points of an ellipse and its auxiliary…
Illustration of a hyperbola and its auxiliary circle. "Any ordinate of a hyperbola is to the tangent…
Illustration of a circle with a sector. "A sector of a circle is the space included between an arc and…
Illustration of intersecting circles. "If two circles intersect each other, the line joining their centers…
Illustration of tangent circles. One circle is said to be tangent to another circle when they touch…
"If from any point on the circumference of a circle, a perpendicular be let fall upon a given diameter,…
"If AOB is an angle of 1 ° on the larger circle, it is also 1 ° on the smaller concentric circle,…
"In trigonometry, the arcs of circles are used to measure angles. All angles are supposed to have their…
Right triangle OCA, inside of Circle O is used to show that side AC is "opposite" O and side OC is "adjacent"…
The coversedsine is equal to 1 minus the sine. In this figure, AE is parallel to OB; hence, EO = AC…
Double Eagle ($20.00) United States coin from 1849. Obverse has a left-facing image of Liberty wearing…
Dollar ($1.00) Obverse sun over dial surrounded by the inscription - CONTINENTAL CURRENCY 1776. Reverse…
Half Cent (1/2 cent) United States coin from 1809. Obverse has a left-facing profile of Liberty surrounded…