Illustration of circle with sector and segment used to find area.

Illustration of partial circle with sector and segment used to find area.

Illustration of a circle with a sector. "A sector of a circle is the space included between an arc and…

Illustration of a sector of a circle. A sector is the space between an arc and two radii drawn to the…

Illustration of a sector of a hollow circle. A sector is the space between an arc and two radii drawn…

Illustrations of a circle with segment, semicircle, sector, quadrant, and central angles drawn.

"Fixed Conensing Light for a Single Sector, 1850.â€”The holophote Light pLp throws its whole light on…

Illustration of an angle &alpha with the vertex at the center, O, of a circle with radius OB. AC and…

"In geometry: (a) A plane figure inclosed between the arc of a circle, ellipse, or other central curve…

An illustration showing a circle sector with radius r, center/central angle v, and length of circle…

An illustration showing a circle sector with center/central angle v and polygon angle w.

Illustration of a right spherical triangle and the five circular parts placed in the sectors of a circle…

Illustration used, with the law of sines, to find the relation between two sides of a spherical triangle…

Illustration used, with the law of cosines, to find the relation between the three sides and an angle…

Illustration used to extend the law of cosines when finding the relation between the three sides and…

Illustration used to extend the law of cosines when finding the relation between the three sides and…

Illustration of a right spherical triangle with a and b the sides, and α and β the angles…

Diagram showing 2 superimposed symmetrical spherical triangles.

An illustration showing a circle with sectors D and E inscribed in a triangle with angles, A, B, and…

Diagram showing a spherical triangle constructed by the intersection of polar arcs.

Diagram showing a spherical triangle constructed by the intersection of polar arcs.

Diagram showing a spherical triangle constructed by the intersection of polar arcs.