1）利用等角的tan值求解

https://www.bilibili.com/video/BV1du411p7Ma

https://www.bilibili.com/video/BV1Kh411F7rg

2）等角“加上/減去”同角或等角

https://www.bilibili.com/video/BV1Vk4y1s7QX

https://www.bilibili.com/video/BV1HX4y1a7AV

https://www.bilibili.com/video/BV1yo4y1M7oM

3）構造相似三角形

https://www.bilibili.com/video/BV1Ac41137Yp

https://www.bilibili.com/video/BV1Fc41137sQ

https://www.bilibili.com/video/BV1rm4y1i7RK

4）其他方法（平行 、 等腰 、 等弧對等角）

https://www.bilibili.com/video/BV1ks4y1e7eS

https://www.bilibili.com/video/BV1M8411Z7RK

https://www.bilibili.com/video/BV1Th4y1V7hG

5）構造三垂直

a.固定頂點

https://www.bilibili.com/video/BV1Hm4y1i78V??

(原題： https://www.bilibili.com/video/BV1yo4y1M7oM）

https://www.bilibili.com/video/BV1Zo4y1u7cN??

(原題： https://www.bilibili.com/video/BV1HX4y1a7AV)

https://www.bilibili.com/video/BV1Bu4y1Z7kZ?

(原題： https://www.bilibili.com/video/BV1du411p7Ma)

b.移動頂點

https://www.bilibili.com/video/BV1yW4y1X74n? ?

（原題： https://www.bilibili.com/video/BV1rm4y1i7RK)

https://www.bilibili.com/video/BV17P411Q7zG? ?

（原題： https://www.bilibili.com/video/BV1Fc41137sQ)

https://www.bilibili.com/video/BV1k8411Z7JH? ?

（原題： https://www.bilibili.com/video/BV1M8411Z7RK)