BGN-1.1.2

Formulae 公式

quadrilaterals 四边形

Refer to the last chapter for symbol representation.
字母含义见上一章。
Square and rhombus 正方形和菱形: 4s4s
Rectangle and parallelogram 长方形和平行四边形: 2(a+b)2(a+b) (aa and bb refer to the side length of two adjacent sides) (aabb 分别指两相邻边的长度)

ellipticals 椭圆形

Call a circle’s circumference (perimeter) CC and diameter dd. Then π=Cd\pi =\dfrac {C}{d} , so C=2πr=πdC=2\pi r=\pi d.
将一个圆的圆周和直径的长度分别称为 CCdd 。易得 C=2πr=πdC=2\pi r=\pi d

Techniques 技巧

When we meet irregular shapes, we can ‘move’ their perimeter without changing it’s value, as below.
当我们遇到不规则图形时,可以在不改边其周界长度当情况下边換其周界,如下。 Image 1.1.2-1 图1.1.2-1 Image 1.1.2-1 图1.1.2-1

Note by Jeff Giff
1 month, 3 weeks ago

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  Easy Math Editor

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Jeff, this is good, but I don't understand Chinese.

Is there any other languages apart from Chinese and English that you can speak?

Yajat Shamji - 1 month, 3 weeks ago

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Nope.

Jeff Giff - 1 month, 3 weeks ago

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Sorry :/

Jeff Giff - 1 month, 3 weeks ago

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That's okay.

Yajat Shamji - 1 month, 3 weeks ago

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