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There are many ways this can be done.

The ancient Greeks measured the lengths of shadows at two different locations a few hundred miles apart on a roughly north-south baseline at noon on the same day of the year. From this using trigonometry the circumference was computed, then using the relationship of circumference to radius the radius can be computed. Almost surprisingly the figure they got was very close to the modern figure.

Columbus repeated this calculation, but due to a combination of bad data in the sources he used (he did not make the measurements himself) and calculation errors on his part he got a result roughly 2/3 of the correct value (an error equivalent to elimination of the Pacific Ocean and the Americas); which convinced him he could easily sail to China & India.

An equivalent calculation can be done using measurements of star positions at night from different locations, using any baseline (e.g. north-south, east-west, diagonals) between the locations as long as the time and day are identical when the measurements are made.

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Q: How to measure the radius of earth?
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How did they measure the diameter or radius of earth?

with a big tape measure


What is planet Earth's diameter?

The mean diameter of Earth is 12,742 kilometers or 7917.5 miles.More specifically, if we quote the accurate values for the radius, it changes depending on where you measure it.Mean radius 6,371.0 km = 3958.8 milesEquatorial radius 6,378.1 km = 3963.2 milesPolar radius 6,356.8 km = 3949.9 miles


WHAT IS the percent error between polar circumference of the earth and real circumference?

There is no error. The Earth is NOT a sphere, it is an oblate spheroid. This is caused by the fact that it is spinning. The spin makes the middle (the equator) bulge out. Thus if you measure the radius to the equator it is 6,378.1 km, while if you measure the radius to a pole it is 6,356.8 km.


How does he find the measure of a radius if he knows the measure of the diameter?

The radius of a circle is half the diameter.


How do you calculate earth's radius?

Eratosthenes (a greek) was the first person known to have accurately measured earth's radius. He did that about 250 BCE. The trick was to measure the length of the shadow cast by the library at Alexandria during the summer solstice, and knowing the distance between Alexandria and Cyene--a city on the Tropic of Cancer. A bit of trigonometry, and earth's radius falls right out.


What is Venus' radius as compared to the Earth's?

It is about 0.949 times Earth's radius.


How do you measure the radius?

measure from the middle out to one side


Who invent radius of earth?

If you are a believer, then God did but if you are not, then nobody did. The radius of the earth existed and therefore ots radius did before there was any form of life on earth to invent it.


How does Venus compare with the earth radius and mass?

Venus' radius = 0.95 of Earth's Venus' mass = 0.815 of Earth's


What is Europa's diameter compared to earth?

Europa: 1561 km radius Earth: 6371 km radius The diameter is twice the radius.


Mercury's radius is what percent of Jupiter's radius?

Mercury's radius is 0.3825 that of Earth Jupiter's radius is 11.209 that of Earth So: (0.3825/11.209)*100 = 3.41 percent.


Do objects on other planets weigh the same as they weigh on Earth?

No. Weight is the measure of how much force a planet pulls an object, that force is determined by the planet's mass and radius, and each planet has a different mass and radius.