Unit 7Measurement2777.2PYRAMIDS, CONES AND SPHERESDo you remember what you learnt about pyramids, cones and spheres in your previousgrades? Can you give some examples of pyramids, cones and spheres from real life?Triangular pyramid Quadrilateral pyramid Pentagonal pyramidabcFigure 7.17ACTIVITY 7.21What is a regular pyramid?2What is a tetrahedron?3Determine whether each of the following statements is true or false:aThe lateral faces of a pyramid are triangular regions.bThe number of triangular faces of a pyramid having same vertex is equal tothe number of edges of the base.cThe altitude of a cone is the perpendicular distance from the base to thevertex of the cone.4UsingFigure 7.18, complete the following to make true statements.aThe figure is called a ______.bThe regionVEDis called a _______.cThe regionABCDEFis called ______.d______ is the altitude of the pyramid.eandVEVFare called ______.Definition 7.2Apyramidis a solid figure formed when each vertex of a polygon is joinedto the same point not in the plane of the polygon(SeeFigure 7.17).ABCDDACEBCABFigure 7.18VFEDCPAB