Circumference: C=2(a+b)(a is long and b is wide)

The aspect ratio of the golden rectangle is

A rectangle (about 0.6 18) is called a golden rectangle.

The golden rectangle gives us a harmonious and symmetrical aesthetic feeling. In order to get the best visual effect, many famous buildings around the world have adopted the design of golden rectangle. Such as the Parthenon in Greece.

Extended data

Application of area method in average problem

When solving the average problem, the traditional solution is usually to calculate the total amount first, and then divide it by the corresponding amount to get the average. However, I find that many children are always puzzled by this explanation, and it is difficult to understand the idea of "moving more and making up less", the core of the average problem. Here, the application of area method is very intuitive

For example, the average score of the contestants selected by Fermat's special training camp for mathematical thinking to participate in a mathematical competition is 75, including male contestants 10 and female contestants 15. The average score of female players is 80. What is the average score of male players?

Traditional solution:

1, first calculate all the total scores according to the average scores of all the players, that is, 75× (10+15) =1875 points;

2. Subtract the total score of female players from the total score to get the total score of male players, that is,1875-80x15 =1875-1200 = 675;

3. Divide the total score of boys by the number of boys to get the average score of boys, that is, 67510 = 67.5.

Area method: one side of the rectangle represents the number of people and the other side represents the average score.

The key point here is to calculate the score (15× 5 = 75) of female players above the average level of all players through the part (5) where the average score of female players (80) is higher than the average score of all players (75), and then provide this extra area (score) to male players.

Then calculate the part where the average score of male players is lower than all the players (75 ÷ 10 = 7.5), and finally subtract the part where the average score of male players is lower than the average value to get the average score of male players (75-7.5 = 67.5).

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