Answer:
The perimeter of the cross section is 30 centimeters.
Explanation:
In this problem we have the intersection of a rectangular prism an a plane.
The dimensions of the rectangular plane are

Assuming the plane is cutting the prism horizontally, the cross section would have dimensions

Because only the height would be cut.
So, the perimeter of the rectangle cross-section is

Therefore, the perimeter of the cross section is 30 centimeters.