Since circular creations appear throughout nature, no man can be credited with the invention of the circle. From the cross-section of a plant stem to the moon and the sun, circles appear everywhere in nature. More »

The unit circle does not have a known creator but was rather an amalgamation of different ideas from early astronomers and mathematicians. Contributors to the technology include the Babylonians, the Egyptians and the Gre... More »

People have practiced the science of astronomy since ancient times and the discipline has no formal inventor. Knowledge of astronomy stretches back prior to recorded history, as evidenced by such ruins as henge circles, ... More »

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Optical illusions have been found in cave paintings, so an optical illusion is not considered an invention but instead is the result of man imitating the geometric forms seen in nature through architecture and art. Arab ... More »

The diameter of a circle is the length of a straight line going from one side of a circle to the opposite side. To measure the diameter, simply choose two points on the edge of a circle that are directly across from each... More »

The formula for the area of a circle is pi multiplied by the radius of the circle squared. The radius of the circle is the length of a straight line stretching from the center of the circle to the line of circumference. ... More »

To calculate a circle's diameter from its circumference, one should divide the circumference by the constant pi, which is an irrational number approximately equal to 3.14159265358979. More »