You need to split the shape into simpler shapes so you would get a rectangular prism and a triangular prism finding the volume is pretty straightforward the formula is
Volume of a triangular prism = area of base triangle × height
The formula for finding the volume of a rectangular prism is the following: Volume = Length * Height * Width, or V = L * H * W. After solving for this you would just have to add the 2 shapes volume together tie get the volume of the composite figure Finding the surface area is also pretty simple since it would only require you to know the formulas
S = 2(lw + lh + wh) to find the surface area of a rectangle or prism
A=12bh is used to find the area of the top and bases triangular faces, where A = area, b = base, and h = height. And by adding the two surface areas of the shapes you can get the surface area of the composite figure but remember to subtract the top face of the rectangular prism and the bottom face of the triangular prism Hope this helps <3
If you take 400 balloons and divide it by 3 balloons; its cause 3 balloons make 1 decoration you get 133.3333333333 decorations in all but, as an estimation is 130 decorations