## How was the circumference of the Earth first measured by?

Eratosthenes

By around 500 B.C., most ancient Greeks believed that Earth was round, not flat. But they had no idea how big the planet is until about 240 B.C., when Eratosthenes devised a clever method of estimating its circumference.

**What is the approximate measure of Earth’s circumference?**

Observations and results In 200 B.C. Eratosthenes estimated Earth’s circumference at about 46,250 kilometers (28,735 miles). Today we know our planet’s circumference is roughly 40,000 kilometers (24,850 miles).

### How was the meter originally defined?

The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth’s circumference is approximately 40000 km.

**How did we measure Earth’s radius?**

To get the size of the earth, he multiplied 900 (distance between two points in kilometers) by 50. He got the circumference as 45,000 kilometers. To get the radius of the earth, he divided the earth’s circumference by 2 and pi.

## Who was the first person to calculate the circumference of the earth and coined the word geography?

Eratosthenes may have been the first to use the word geography. He invented a system of longitude and latitude and made a map of the known world. He also designed a system for finding prime numbers — whole numbers that can only be divided by themselves or by the number 1.

**What is the unit of Earth?**

Astronomical unit | |
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The grey line indicates the Earth–Sun distance, which on average is about 1 astronomical unit. | |

General information | |

Unit system | Astronomical system of units (Accepted for use with the SI) |

Unit of | length |

### What is the circumference of the Earth at 45 degrees latitude?

At the equator, the circumference of the Earth is 40,070 kilometers, and the day is 24 hours long so the speed is 1670 kilometers/hour ( 1037 miles/hr). This decreases by the cosine of your latitude so that at a latitude of 45 degrees, cos(45) = . 707 and the speed is . 707 x 1670 = 1180 kilometers/hr.

**How do you calculate the circumference of the Earth’s orbit?**

Circumference of the Earth’s Orbit = 2*pi*R = 942,000,000 kilometers. Time to complete one Orbit = 365.2422 days = 8766 hr. Speed of Revolution = Distance/Time = 942,000,000 km / 8766 hr = 107,000 km/hr = 30 km/sec.

## What is the circumference of radius of the earth?

about 24,901 miles

Radius, diameter and circumference The planet’s rotation causes it to bulge at the equator. Earth’s polar radius is 3,950 miles (6,356 km) — a difference of 13 miles (22 km). Using those measurements, the equatorial circumference of Earth is about 24,901 miles (40,075 km).

**What is Earth diameter and circumference?**

Earth’s circumference (the distance all the way around the equator) is 24,901 miles (40,075 kilometers). Its diameter (the distance from one side to the other through Earth’s center) is 7,926 miles (about 12,756 kilometers).

### How is the circumference of the Earth measured in meters?

In other words, meter was defined as 1/10,000,000 of the distance from the Earth’s equator to the North Pole measured on the circumference through Paris. Using this unit, the circumference of perfectly round Earth should be exactly 40,000, 000 meters (or 40,000 km).

**How are modern units of measure connected with the planet?**

Modern units of measure are connected with the SIZE of our planet. Originally, the meter was designed to be one ten-millionth (1/10,000,000) of a quadrant, the distance between the Equator and the North Pole.

## How did our ancestors measure the size of the Earth?

Ancient units of measure reveal that our ancestors were able to measure the size of our planet with very reasonable accuracy… In the writings of Eratosthenes, he estimated 250,000 stadia for circumference of the earth. Strabo and Pliny indicated 700 stadia for a degree which gives 252,000 stadia for the circumference of the Earth.

**Why do we use the ancient units of measurement?**

This unit of measurement is used by all nations for air and sea travel. Ancient units of measure reveal that our ancestors were able to measure the size of our planet with very reasonable accuracy… In the writings of Eratosthenes, he estimated 250,000 stadia for circumference of the earth.