Final answer:
The WGS-84 model of the earth's surface is represented by an ellipsoid equation. Curves of equal latitude are circles on the ellipsoid, with smaller circles near the poles and larger circles near the equator. Meridians (curves of equal longitude) on the ellipsoid are ellipses with varying eccentricity.
Step-by-step explanation:
A) Finding the equation of the earth's surface as used by WGS-84:
The equation of the earth's surface as used by WGS-84 can be represented as an ellipsoid with the center at the origin (0,0,0). The equation is:
x²/a² + y²/a²+ z²/b²= 1
where 'a' is the distance from the center of the earth to a point on the equator (6378.137 km) and 'b' is the distance from the center of the earth to the poles (6356.523 km).
B) Shape of curves of equal latitude:
Curves of equal latitude, which are traces in the planes z = k, will be circles on the ellipsoid. These circles will be smaller near the poles and larger near the equator.
C) Shape of meridians (curves of equal longitude):
Meridians are traces in planes of the form y = mx. On the ellipsoid, these meridians will be ellipses with varying eccentricity based on the value of m.