Throw a cube dice with uniform texture (the number of points on each side is 1, 2, 3, 4, 5, 6, and the sum of the points on the opposite side is equal) to make the top points.

According to the fact that the bottom is longer than the upper bottom, there are the following situations, as shown below: (The picture is not standard, just to illustrate the problem, don't worry. )

Figure 1? Figure 2 Figure 3 Figure 4 Figure 5? Figure 6?

In Figure 5 and Figure 6, there are 1 time (i.e. 2 kinds) when the upper bottom is 3, and there are 0+ 1+2+3+4 = 12 possibilities in total.

So the probability of forming an isosceles trapezoid is: 2/ 12= 1/6.

My understanding is that except for the other waist, you must use the repeated number (isosceles trapezoid), and the upper and lower soles cannot use the repeated number. If it can be repeated, the answer will be different (2/ 15)

Don't blindly believe other people's answers, learn to analyze by yourself. Think about it: Does every situation fit the meaning of the question?

Wish progress!