Then connect these two points.

There are two ways: one is to intersect with a 2cm edge, and the other is to intersect with a 4cm edge.

Calculate by Pythagorean theorem respectively

(2 * 2+5 * 5) 0.5 = 29 0.5, which is the root number 29.

(3*3+4*4)^0.5=5

29^0.5>； five

So the shortest is 5cm.

Climb forward first, intersect with the edge of 4cm, and then climb down.