A paper strip is rolled and then cut with two planes at 45 degree as shown below. The middle part of the cut paper is unrolled. Which of the options represents this part?
The problem involves visualizing how a paper strip, rolled then cut at a 45-degree angle, looks when the middle part is unrolled. Let's break it down:
The initial setup includes a rolled paper strip. When this strip is cut by two planes each at a 45-degree angle, it creates a unique cross-section.
Imagine these cuts as making diagonal lines across the cylindrical shape of the rolled paper, resulting in a cut that is not perpendicular to the central axis but rather at an angle, creating inclined edges on the circular face.
Upon unrolling the middle section of this paper strip, the effect of the angled cuts will manifest as slanted surfaces on either end of the rectangle strip.
With these points in mind, among the given options, the middle section—when unrolled—will have the shape where the edges are diagonally slanted, leading to a parallelogram. This aligns precisely with the correct option.
