Answer:
2. b : l
3. 20cm
4. 49 
5. 
Step-by-step explanation:
<u>Solution 2:</u>
Let cylinder is rolled along 'l':
Height of cylinder , h = length of rectangle = l
Perimeter of base = b
Let 'r' be the radius of cylinder's base:

Volume of a cylinder is given as:

Putting the values:

Let cylinder is rolled along 'b':
Height of cylinder , h = length of rectangle = b
Perimeter of base = l
Let 'r' be the radius of cylinder's base:

Volume of a cylinder is given as:

Putting the values:

Taking ratio:

Solution 3:
Rectangle is rolled along its length to make a cylinder, so height will be equal to its length.
 height of cylinder = 20 cm
 height of cylinder = 20 cm
Solution 4:
Side of square = 7 cm
Height of cylinder =Side of square = 7 cm
7 cm will be the circumference of the circle.
i.e.  = 7 cm
 = 7 cm
Curved surface area of a cylinder:

Putting the above values:
CSA = 7  7 = 49
 7 = 49 
Solution 5:
As calculated in above step:
CSA =  7
 7  7 = 49
 7 = 49 
Total surface area = 
Calculating value of r:
 = 7 cm
 = 7 cm

Total surface area = 

Ratio of TSA: CSA is
