Traditionally, the earth's surface has been modeled as a sphere, but the world geodetic system of 1984 (wgs-84) uses an ellipsoid as a more accurate model. it places the center of the earth at the origin and the north pole on the positive z-axis. the distance from the center to the poles is 6356.523 km and the distance to a point on the equator is 6378.137 km.(a) find an equation of the earth's surface as used by wgs-84.(x^{2}/(6378.137)^{2})+(y^{2 }/(6378.137)^{2})+(z^{2}/(6356.523) ^{2})=1 (this is the correct answer)(b) curves of equal latitude are traces in the planes z = k. what is the shape of these curves? these curves are circles given by the family of equations (in terms of x, y, and k) ) meridians (curves of equal longitude) are traces in planes of the form y=mx. what is the shape of these meridians? these meridians are ellipses given by the family of equations (in terms of x, z, and m)