Homework Help: Math: Arithmetic: General History of Math

In ancient Egypt, the standard measurements of length were the cubit, digit, palm, span, foot, and yard.

Four digits = One palm
Two palms = One span
Two spans = One cubit

The angle most commonly used in architecture is a 90° angle, or a right angle. Bricks are made out of right angles in every corner so that they stack together in vertical piles. This means that walls stand up straight and floors are level.

The modern way of making a right angle is to measure out 90° with a protractor, but there are ways of making a right angle without a protractor. A bricklayer makes right angles with strings. He makes one string horizontal with the help of a level surface, and makes the other string vertical by hanging a weight from the end. A draftsman makes a right angle by drawing two circles that cross each other. He then draws a straight line between the points at which the circles cross, and another between the centers of the circles.

In ancient Egypt, surveyors made right angles by "rope-stretching." They used a long rope that was divided into twelve equal spaces by knots. One man held the two ends of the rope together. A second man held the knot that was three spaces from the end. A third man held the knot that was four spaces from the end. When the rope was stretched tightly it formed a right angle.

The Pythagorean Theorem was discovered approximately 2500 years ago by a Greek mathematician known as Pythagoras. The rule says that in every right triangle, the square of one leg plus the square of the other leg equals the square of the hypotenuse.

In algebra, we let letters stand for numbers. It is like using a code for saying many thing in a short space. In this code we do not use X to stand for multiplication because it may be confused with the variable x. We show multiplication by using a small middle-dot.

Many statements can be made about numbers or space. Some of the statements are true, and some are false. We find out which ones are true by following the rules of logic, or careful thinking.

To erect such stupendous buildings, the architects of Egypt had to know how to make some kind of ground plan, how to level the edges of stone blocks, how to haul them up from the ground, and how to set them fairly and squarely in position. In learning all this, the pyramid architects were making practical discoveries in the art of measurement, or as we now say, geometry.

One of the world's oldest and largest buildings in the world are the pyramids of Giza in Egypt. The Great Pyramid of Giza is the largest tomb ever built.

Homework Help: Math: Arithmetic

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