Answer:
12
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer: 423.11 m^2
Step by step explanation:
Area of a circle formula pi*r^2
First solve the area of the big circle 
3.14*21^2=1384.74 m^2
Now find the are of the smaller circle 
r=21-3.5=17.5
3.14*(17.5)^2=961.63 m^2
Now we can minus the small area off the big area to get the shaded area. 
1384.74-961.63=423.11 m^2
So the area of the shaded region is 423.11 m^2
        
             
        
        
        
Answer:
42 miles
Step-by-step explanation:
If it's a constant 12 miles per hour then it would be 
12 mph x 3 hours = 36 
then you would add that with the 1/2 hour for
12 mph x 1/2 hours = 6
36 + 6 = 42 miles traveled
 
        
             
        
        
        
125 = 5 * 5 * 5 = 5^3
Its a perfect cube.
        
                    
             
        
        
        
Answer:
Nifal received $ 4 for washing the first car.
Nifal received $ 5 for washing the second car.
4 and 5 have a sum of 9.
Step-by-step explanation:
The problem can be rewritten as follows: Find the sum of two consecutive entire numbers equal to 9. That is:


Then, by eliminating y:
 

Now, let is clear 
:


Nifal received $ 4 for washing the first car.
The earning for the second car is: (
)



Nifal received $ 5 for washing the second car.
4 and 5 have a sum of 9.