Answer:
B: 144 yd²
Step-by-step explanation:
It's a square pyramid : Base area 8 x 8 = 64
4 side area:((8 x5) /2) x 4 = 80
Total area: 64 +80 = 144
 
        
             
        
        
        
Yes, they are proportional because if you increase or decrease either amount they will both change. They will always have the same size. For example if I want to double the flour, I will have to double the milk as well because they have the same ratio. 
        
                    
             
        
        
        
The answer would be 10.
6 + 5 = 11
11 x 9 = 99
This means 9(6+5) = 99
99 - 89 = 10
        
             
        
        
        
Answer:
It seems there's more information in you question that you haven't posted.
7 months = 7 * (365/12) = 213 days
The half-life of chromium 51 is 27.7 days.
After 7 months, chromium 51 will have undergone 7.69 half-lives.
To solve for the ending amount we'll use the formula:
Ending Amount = Beginning Amount / 2^n where 'n' = # of half-lives
We'll say the beginning amount =1
Ending Amount = 1 / 2^7.69
Ending Amount = 0.0048426082
Basicaly if you started with 1 gram of chromium 51, after 7 months you would have 0.0048426082 grams.
Source: https://www.1728.org/halflife.htm
Step-by-step explanation: