GSEB Solutions for Class 8 Mathematics – Area and volume of cylinder

GSEB Solutions for Class 8 Mathematics – Area and volume of cylinder (English Medium)

GSEB SolutionsMathsScience
Exercise

Solution 1:
Diameter (d) of the cylindrical tin = 80 cm = 0.8 m
Thus, the radius (r) of the cylindrical tin = 0.4 m
Height (h) of the cylindrical tin = 1.5 m
Curved surface area of the cylindrical tin = 2πrh
= 2 × 3.14 × 0.4 × 1.5
= 3.768 m²
Thus, the curved surface area of the cylindrical tin is 3.768 m².

Solution 2:

Solution 3:

Solution 4:

Solution 5:

Solution 6:

Solution 7:

Practice 1

Solution 1:

Solution 2:

Solution 3:

Solution 4:
Radius (r) of the cylinder = 20 cm
Height (h) of the cylinder = 30 cm
Curved surface area of the cylinder = 2πrh
= 2 × 3.14 × 20 × 30
= 3768 cm²
Thus, the curved surface area of the cylinder is 3768 cm².

Solution 5:

Practice 2

Solution 1:

Solution 2:

Solution 3:

Solution 4:
For the given cylindrical chimney,
Diameter d = 80 cm = 0.80 m and height h = 12.5 m.
Curved surface area of the cylindrical chimney
= πdh
= 3.14 × 0.80 × 12.5
= 31.4 m²
Cost of painting 1 m² area = Rs. 140
∴ Cost of painting 31.4 m² area = Rs. (140 × 31.4)
= Rs. 4,396
Thus, the cost of painting the chimney from outside is Rs. 4,396.

Solution 5:

Solution 6:

Practice 3

Solution 1:

Solution 2:

Solution 3:

Solution 4:

Solution 5:
For the cylinder tank of milk,
Radius (r) = 25 cm and height (h) = 2 m = 200 cm
Volume of the milk stored in the cylindrical tank
= Volume of the cylinder
= πr²h
= 3.14 × 25 × 25 × 200
= 3,92,500 cm³
Now, 1 cm³ = 1 ml
∴ 3,92,500 cm³ = 3,92,500 ml
Thus, the volume of the milk in the tank is 3,92,500 ml.
Number of bags filled with 500 ml of milk = 1

Solution 6: