As per given information in the question,
Let us assume two trees are denoted by PQ and RS and O be a point on the street PR, which is the distance between the two trees.
Then,
We Assume that OS and OQ represent the ladder which at rest on both trees.
Then,
In ΔORS,
Now as we know,
Now, consider ΔPQO,
As we know,
Therefore,
Hence the width of the street PR is .