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
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
Curved surface area of a cylinder:
Putting the above values:
CSA = 7 7 = 49
Solution 5:
As calculated in above step:
CSA = 7 7 = 49
Total surface area =
Calculating value of r:
= 7 cm
Total surface area =
Ratio of TSA: CSA is