Reflection line of reflection y=2
Not too sure could be rotation maybe
Answer:

Step-by-step explanation:
Total Surface Area of cylinder = Lateral Surface Area + Area of both circle bases.
Lateral Surface Area = Circumference of Circle
Height
Lateral Surface Area = 
Area of one circle base: 
Area of both circle bases: 
Total Surface Area = 
It should be :
1/3(x + 18) = 7
1/3x + 6 = 7
1/3x + 6 - 6 = 7 - 6
1/3x = 1
x = 3
6km is same as 6000m so the answer is no, 6km is not greater than 6000m. Both value are the same.
I hope this helped you.
Have a wonderful day!