Shortest distance around a pyramid

Hint:

The distance has to be a straight line along the net of the pyramid. There are two options:

The first line has lenght $10\sqrt{7+2\sqrt{3}}$, and the second one has $10\sqrt{7}$, which is the smaller one.

Draw the net of the pyramid and use the cosine rule.

Hint: Draw the net diagram of the square pyramid and the you will find two points that are mid-point of $OR$. As you know that, minimum distance between any two points is the straight line joining them, just connect $P$ and midpoint of $OR$ by a straight line. Then just find the length of this line and exclude the length of this line that goes out of the net diagram. This length of line will be minimum length. Why?

Note: You can choose any one of the two midpoint because since the diagram is symmetric, the two lengths will be the same.