Answer:
1.25
Step-by-step explanation:
 
        
             
        
        
        
Answer: 40
Step-by-step explanation:
138/x = 207/60
8280 = 207x
divide by 207
40 = x
 
        
             
        
        
        
Answer:
A = 225 m ^2
Step-by-step explanation:
The perimeter of a square is found by 
P =4s where s is the side of a square
60 = 4s
Divide each side by 4
60/4 =4s/4
15 = s
Now we need  to find the area
A = s^2 for the area of a square
A = 15^2
A = 225 m ^2
 
        
             
        
        
        
Ok so you have to know the formula density=mass/volume (density is the measure of how much mass is in each unit of volume)
the mass, as measured is 12.9 g
for the volume, to find the volume of the cube multiply the length times the width times the height. Or , since it's a cube, just cube 8
V=8*8*8=512 cm^3
therefore, density= 12.9 g/512 cm^3
since you need to have 1 cm^3 on the bottom, this simplifies to about 
.025 g/cm^3