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Home Base:
A principal section of a pyramid is a section cut by a plane parallel to the base and lying between the base and vertex. It is a polygon similar to the base polygon, such that the lengths of corresponding sides of the section and the base are proportional to their distances from the vertex A, and the areas of the principal section and the base are proportional to the squares of their distances from A.There is no CB channel monitored by the U.S. Coast Guard, and there is no connection with the telephone system ashore. The range of CB radios is up to about 10 miles, but the distance may be greater to a base station ashore with a high antenna. A skipper may set up such a base operation at home base or carry a hand-held set ashore for communicating back to his Boat at anchor. While true marine radios must be used only for ship's business, there is no such restriction on CB sets. In areas where the Coast Guard is not operating, CB radios often provide the only means for calling for help in an emergency.
PYRAMID, in geometry, a polyhedron of which one face is a plane polygon b of area B called the base, and the remaining faces, called lateral faces, are triangles having a common vertex A not in the plane of the base. The line segments AB, AB2, ..., ABn joining the vertex A of the pyramid to the vertices Bi, 82, ..., Bnof the base polygon (see diagram) are called lateral edges. The segment AP drawn perpendicularly from A to the plane of the base, and its length h, are both called the altitude of the pyramid. The volume V of the pyramid is V = 3 Eh. The center of gravity (centroid), G, of the pyramid lies one-fourth of the way from the centroid M of the base to the vertex A.
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