Mathematics for Grade Five was published by East China Normal University Press in June, 2008 1 and compiled by the editorial team of East China Normal University Press. This book mainly summarizes and explains the mathematics knowledge of grade five. The sixth chapter sorts out and perfects its contents:

Exercise 6.6 Area of Graph (1)

Exercise 6.7 Area of Graph (2)

Extended data

Pi is the ratio of the circumference to the diameter of a circle, which is generally expressed by the Greek letter π and is a common mathematical constant in mathematics and physics. π is also equal to the ratio of the area of a circle to the square of its radius. Accurate calculation of geometric shapes such as circle perimeter, circle area and sphere volume is the key value. In the analysis, π can be strictly defined as satisfaction crime? x？ The smallest positive real number x =0.

Pi in Greek letters? π (pronounced pài) is a constant (approximately equal to 3. 14 1592654), which is the ratio of circumference to diameter. It is an irrational number, that is, an infinite cycle decimal. In daily life, pi is usually expressed as 3. 14, which is used for approximate calculation.

1965, the British mathematician JohnWallis published a mathematical monograph, in which he deduced a formula and found that pi is equal to the product of infinite fractions. 20 15 scientists at the university of rochester found a formula with the same pi in the quantum mechanical calculation of hydrogen atomic energy level.

Baidu encyclopedia-fifth grade mathematics