Answer:
BC ≈ 14.7 m
Step-by-step explanation:
Using the Sine rule in Δ ABC
 = 
To find ∠ A subtract the 2 given angles from 180°
∠ A = 180° - (90 + 28)° = 180° - 118° = 62°
Then
 = 
 ( cross- multiply )
BC × sin28° = 7.8 × sin62° ( divide both sides by sin28° )
BC = 
 ≈ 14.7 m ( to 3 significant figures )
 
        
             
        
        
        
Here is how to work 2, 3 , and 4.
 
        
             
        
        
        
B² - 4ac 
= 8² - 4*(-2)*(-9) 
= 64 - 72
= -8
        
             
        
        
        
Answer:
about 78 years 
Step-by-step explanation:
Population
y =ab^t  where a is the initial population and b is 1+the percent of increase  
    t is in years
y = 2000000(1+.04)^t
y = 2000000(1.04)^t
Food
y = a+bt   where a is the initial population and b is constant increase
    t is in years
b = .5 million = 500000
y = 4000000 +500000t
We need to set these equal and solve for t to determine when food shortage will occur
2000000(1.04)^t= 4000000 +500000t
Using graphing technology, (see attached graph  The y axis is in millions of years), where these two lines intersect is the year where food shortages start.
t≈78 years
 
        
                    
             
        
        
        
After you cut off 6 pieces, the rope is 18.25 inches long