LZ can be AE, BF⊥ PQ in E and F (not to say that Baidu users can't post pictures).

Let the river width be x, then ed = x÷tan 60 = x triple root.

DF = 50-(x÷tan 60)CD = 1 10。

So CF = CD-DF =110-(50-x ÷ tan 60) = 60+(x ÷ tan 60), right?

BF = cf×tan 30 = 20√3+x- one third.

And MN∑CQ, AE=BF=x, then equation 20√3+ three-thirds x=x can be listed.

Solve the equation to get x=30√3 (thirty times the root number three).

Whether there is a score or not, I still hope to adopt it! In addition, I wish you a happy study!