Besides, the question asked in the OP has been answerved.
Yes, your question was answered!
Difference between equatorial and polar diameters is 0.35%.
With error of 0.35% you can use approximation from "almost-circle" to "circle".
Draw ellipse 7.898 inches high and 7.926 inches wide.
Would you be able to see the deformation of 0.028 inches?
The thickness of the line you draw is 0.7 milimeters, which is roughly 0.028 inches.
You could google this for yourself:
"The mean radius of Earth is 3,959 miles (6,371 kilometers).
However, Earth is not quite a sphere.
The planet's rotation causes it to bulge at the equator.
Earth's equatorial diameter is 7,926 miles (12,756 km),
but from pole to pole, the diameter is 7,898 miles (12,714 km)
— a difference of only 28 miles (42 km)."
So, equator is 14 miles farther from the center of the earth than poles.
So,
"With error of 0.35% you can use approximation from "almost-circle" to "circle"."But it is not
precisely an oblate spheroid (ellipsoid). The exact shape deviates very slightly from this and is "a little chubbier south of the equator". You might have read:
The actual shape of the earth is described as the "Geoid": Geoid
The geoid is the shape that the surface of the oceans would take under the influence of Earth's gravitation and rotation alone, in the absence of other influences such as winds and tides. This surface is extended through the continents (such as with very narrow hypothetical canals). All points on the geoid have the same gravity potential energy (the sum of gravitational potential energy and centrifugal potential energy). The force of gravity acts everywhere perpendicular to the geoid, meaning that plumb lines point perpendicular and water levels parallel to the geoid.
Much more in Wikipedia, Geoid
This is not a simple shape as it is a sphere distorted by rotation and by the unequal distribution masses around the earth.
Description
The geoid surface is irregular, unlike the reference ellipsoid, which is a mathematical idealized representation of the physical Earth, but considerably smoother than Earth's physical surface. Although the physical Earth has excursions of +8,848 m (Mount Everest) and −429 m (Dead Sea), the geoid's variation ranges from −106 to +85 m, less than 200 m total compared to a perfect mathematical ellipsoid.[/size]
Because the actual geoid is so complicated a reference ellipsoid is used as a mathematical model for calculation purposes.
As noted above the differences are small, ranging from −106 to +85 m.
Simpler and more complex "mathematical models" are used depending on the application.
So the earth is not exactly an ellipsoid (an oblate spheroid), but is close enough to one for most purposes.
The comment that it is "slightly pear-shaped" comes from the fact that South of the Equator the earth is minutely bigger than North of the Equator, though still within this −106 to +85 m of the perfect mathematical ellipsoid.
So his "
Royal Perfection, the Most Precise Majestic NXXX"
demands absolute precision!
Tough cheese
In this life we have to accept that not everything can be done with absolute precision. The earth is not a "mathematical geometric body". It is a real physical object made up earth, rock, water etc and the only way to determine its size and shape is to measure it!
So it has been measured, in the early days by simple instruments, then to laser interferometers etc and finally to satellites.
So the shape is now defined as a reference ellipsoid with very small deviations of −106 to +85 m of the perfect mathematical ellipsoid, and this final shape is known as the "geoid".
The relative errors involved here are -0.0017% to 0.0013% in the earth's radius.
Now if
The Great Bag Full of Useless Hot-air (AKA N30) is not satisfied with that, I respectfully suggest he get out his trusty Lufkin tape
and measure it for himself!
Yes, your
Royal Perfection, the Most Precise Majestic NXXX, your question in the OP has been answered.
Now,
just to prove that you are not a hypocrite, your Wiki, which you undoubtedly accept without question states that:
The Ice Wall
The figure of 24,900 miles is the diameter of the known world; the area which the light from the sun affects.
Please show me exactly where that figure came from. Remember, it is supposedly a flat earth, so measurements shouls be easy.
Prove to my satisfaction that it is 24,900 miles and not 24,899 miles or 24,901 miles.
There, a whole mile tolerance!