In week 3, I learned about trigonometry.

First, there are three sides to the triangle.

One of them is adjacent. It is located beside the reference angle.

The other one is the opposite side. It is located across the reference angle.

And the last one is the hypotenuse. It is always located across from 90°. And also it is the longest side of the triangle.

Here is the example of the triangle.

And then, we learned about ratios.

There are also three ratios.

sine ratio= opposite side/hypotenuse

cosine ratio= adjacent/hypotenuse

tangent ratio= opposite side/adjacent

I had learned about this in Japan. In Japan, I learned this way.

opposite side=y                    sine ratio=y/r

adjacent=x                            cosine ratio=x/r

hypotenuse=r                       tangent ratio=y/x

I learned like this. In Japan, we change the word(opposite side, adjacent, hypotenuse)easily and help understand the ratio.

Finally, I thought there are many ways to learn something and it is different in each country. I felt it in many cases of math and it is funny.

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