Table of Contents

## Who is the father of circumference?

What is Eratosthenes famous for? Eratosthenes measured Earth’s circumference mathematically using two surface points to make the calculation.

**Where did circumference of a circle come from?**

The perimeter of a circle is called the circumference and is the linear distance around the edge of a circle. The circumference of a circle is proportional to its diameter, d, and its radius, r, and relates to the famous mathematical constant, pi (π).

**Who invented perimeter of circle?**

Archimedes

The first mathematician known to have used this kind of reasoning is Archimedes, who approximated the perimeter of a circle by surrounding it with regular polygons.

### Who Discovered size of Earth?

Eratosthenes of Cyrene

The first person to determine the size of Earth was Eratosthenes of Cyrene, who produced a surprisingly good measurement using a simple scheme that combined geometrical calculations with physical observations. Eratosthenes was born around 276 B.C., which is now Shahhat, Libya. He studied in Athens at the Lyceum.

**Who invented area?**

In the 7th century CE, Brahmagupta developed a formula, now known as Brahmagupta’s formula, for the area of a cyclic quadrilateral (a quadrilateral inscribed in a circle) in terms of its sides.

**Why is it called circumference?**

The Latin word circum means “around,” and the root ferre is the Latin verb for “carry,” so imagine carrying a puppy around a circle pit of lava: the path you walk is the circumference.

## Who gave value of pi?

Archimedes of Syracuse

The Egyptians calculated the area of a circle by a formula that gave the approximate value of 3.1605 for π. The first calculation of π was done by Archimedes of Syracuse (287–212 BC), one of the greatest mathematicians of the ancient world.

**Who named Planet Earth?**

All of the planets, except for Earth, were named after Greek and Roman gods and godesses. The name Earth is an English/German name which simply means the ground. It comes from the Old English words ‘eor(th)e’ and ‘ertha’.

**How old is the Earth?**

4.543 billion years

Earth/Age

Earth is estimated to be 4.54 billion years old, plus or minus about 50 million years. Scientists have scoured the Earth searching for the oldest rocks to radiometrically date. In northwestern Canada, they discovered rocks about 4.03 billion years old.

### Who was the first person to measure the circumference of the Earth?

The first accurate measurement of the circumference of the Earth was performed by the Greek mathematician Eratosthenes, who lived from ca. 276 BC to ca. 195 BC (we don’t know the exact year when he performed his experiment).

**When was the ratio of circumference to diameter of a circle invented?**

The history of the constant ratio of the circumference to the diameter of any circle is as old as man’s desire to measure; whereas the symbol for this ratio known today as π ( pi) dates from the early 18th century.

**When did Archimedes measure the circumference of a circle?**

In Measurement of a Circle written circa 250 BCE, Archimedes showed that this ratio (C/d, since he did not use the name π) was greater than 31071 but less than 317 by calculating the perimeters of an inscribed and a circumscribed regular polygon of 96 sides.

## How is the circumference of a circle calculated?

Circumference = π × diameter = 2 π × radius. In geometry, the circumference (from Latin circumferens, meaning “carrying around”) is the perimeter of a circle or ellipse. That is, the circumference would be the arc length of the circle, as if it were opened up and straightened out to a line segment.