It looks like you're doing good with breaking-down the composite into digestible pieces. So, don't stress too much!
Keep in mind that the area for a 3D shape is Bh, where "B" is the area of a face & "h" is the height.
#5
Shape A is 3X4X9.
First, calculate the area of a face:
9X4= 36
Multiply by height:
36X3= 108
The process is the same with shape B.
3X4X8
Calculate area of face:
8X4= 32
Multiply by height:
32X3= 96
Now you add both areas:
108+96= 204 cubic feet
I think you're doing pretty good, just don't over think things too much. Try #8 with the similar process seen here. Just comment if you get stuck.
Hope this helps!
Answer:
52 cubic units
Step-by-step explanation:
1. Divide the shape into 2 parts:
The first one: a 2 by 4 by 6 rectangular prism.
The second one: a 1 by 4 by 1 rectangular prism.
2. Find the volumes of the prisms.
2*4*6=48
1*4*1=4
3. Add the two volumes
48+4=52 cubic units (or units^3)
1 and 2 are less then 3
4=3+1 but you cant get 1 from 7 or 3 so 4 is impossible. So is 5, 6, 8, and 20.
Bolded numbers are answers.
2x - 10 = 30
2x = 40
x = 20