Mathematics

Question

Comments

看不懂。。。

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都是英文和国文的

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写了答案，我用英文解释，望理解。

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太多字了不想看。

Answer 1

【For question number 5, we need to use Form 1 maths knowledge 】

【As some people think that my method is complicated, so I will try to include to methods, and I really wish you understand this 2 methods.】

5) Method 1: Slower way

We all know that the sum of all interior angle is 360°.

So x+y= 360°-90°-90°=180°

The answer is B.

Method 2: Fastest way

As the diagram below is a trapezium, such that AB is parallel to CD.

x+y=180° (interior angle 同旁内角）

The answer is B.

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6）

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“The length of the arc of the rear wheel which is subtended by angle of 45° is 13.75cm.”

Now, we can think this question statement in this way, 

As 360➗45=8 ，when we divided a circle into 8 equally parts, then the angle subtended of the sector is 45°. 

Answer 2

5.B  x+y=360°-90°-90°

                =180°

Comments

不对，为什么你最后要➗2，正确答案直接是 360°-90°-90° 就行了

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不好意思，打错

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我修改了，希望没人看错steps

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ok

Answer 3

hiehie我再仔细地用华文跟你解释第五题bar

首先我们知道四边形的内角和都是360°，所以我们就可以得出

90°+90°+x+y = 360°

180°+x+y = 360°

x+y = 360° - 180°

x+y = 180°

第二个楼上的就是正解，他的很好理解，我就不解释了

(●'◡'●)

Comments

所以 我的第5题解释难明白吗？哪里不明白，谢谢你。

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不是这个意思呢，我不是讲你的回答很难明白，我指的是另一个人的回答，另一个人的回答没有那么细致，我只是针对他的回答再加以解释，你的回答没有问题

Answer 4

5.keywords ：四边形内角角度总和360°

额外：三角形内角角度总和就是180°

x+y+90°+90°=360°

 x+y+180°      =360°

             x+y    =360°-180°

                       =180°（B）

6.I never learn before (sorry)