How to choose 7 questions in 20 12 national mathematics examination paper? For example, the side length of a small square on the grid paper is 1, and the thick line draws three views of a geometric figure. What are these? Solution: According to the three views, this geometric figure is a four-corner cone, the bottom is a square with a side length of 2, and the diagonal length of the bottom is 2√2.

The height of the side perpendicular to the bottom surface is 2.

So the length of the longest side is

√﹙2√2+2^2﹚ =2√3

The longest side of this polyhedron is 2√3.