Hi 
Yes 15 kilometers is 1500000 cm
This is because in metric conversion, you multiply by ten each time you convert to the next unit.
Heres a useful way to remember
K ing (kilo)
H enry (hecto)
D oesn't (deca)
U sually (unit) <-metre, litre ect.
D rink ( deci)
C hocolate (centi)
M ilk (milli)
        
             
        
        
        
Answer:
1)· 5x + 2y = 9. First we solve for y. 2y= 9 -5x. y=(9-5x)/2. Now that we have the value of y. We substitute on the original equation and resolve. 5x + 2y = 95x + 2y = 9  5x + 2(9-5x)/2 = 9  5x + 9 - 5x = 9  9 = 9
That would be x = 1  
Now substitute and resolve to find y.  
5(1) + 2y = 9
5 + 2y = 9
2y = 4
y = 2
So our answer x=1 and y = 2. (1,2)
Proof :  
5(1) + 2(2) = 9
5+ 4 = 9
9 = 9
Step-by-step explanation:
hoped it helped for the first  one  i didnt now the second one
 
        
             
        
        
        
You are now on the 5th floor. 
0 - 1
1 - 2
2 - 3
3 - 4
4 - 5
        
             
        
        
        
Since a pentagon has 5 sides, you would divide the perimeter by the number of sides.
641.5/5 = 128.3cm
Therefore, the length of one side of the pentagon is 128.3cm.