According to the coordinate characteristics of point A and point B, if the straight line AB∑x axis, the point with a distance of 4 from the straight line AB is on a straight line parallel to the straight line with a distance of 4 from the straight line AB, and there are two straight lines. According to the fact that the midline on the hypotenuse of a right triangle is equal to half of the hypotenuse, the midpoint of AB is the center of the circle, and the intersection of an arc and two straight lines with radius of 5 is the third vertex of the right triangle;

According to the fact that the median line on the hypotenuse of a right triangle is equal to half of the hypotenuse, taking the midpoint of AB as the center, C2 and C3 (taking C2 and C3 as right angles) intersect with a straight line with a height of 4, and so do C6 and C7.