1. 1 Because the bottom is square, the length and width of the rectangle are equal: 8/4 = 2[ decimeter].

Because it is square after unfolding, the height is equal to the perimeter of the bottom: 8[ decimeter].

3 cuboid product 2*2*8=32[ cubic decimeter]

2. The shaded part of 1 is a triangle, and the height of the trapezoid can be calculated according to the triangle area formula:

15*2/6=5[ cm]

2 trapezoidal area: [6+ 10]*5/2=40[ cm2]