动点问题是初中数学的一个难点,中考经常考察.有一类动点问题,题中未说到圆,却与圆有关,只要巧妙地构造圆,以圆为载体,利用圆的有关性质,问题便会迎刃而解;此类问题方法巧妙,耐人寻味. The dynamic point problem is a difficult point in junior high school mathematics. The examination is often investigated. There is a kind of dynamic point problem. The circle is not mentioned in the question, but it is related to the circle. As long as the circle is constructed skillfully, the circle is used as a carrier, and the relevant nature of the circle is used. This will solve the problem; this kind of problem is clever and intriguing.