The second question: this is the general's horse drinking problem, which will be talked about when he learns to be symmetrical in Grade Two.

1, make a point about the river A 1 symmetry point.

2. Connecting points A 1 and B, this line will have an intersection with the river, that is, the location of the water tower, and the water pipe is the shortest.

As a symmetrical point of point B, it is also possible, as above.

Question 1: Because trees are planted at both ends, they are not counted in 360. The formula is: 360 ÷ (74-2) ÷ 2 =10m.

Hope to adopt