Two solid cubes each of volume 8,000 cm³ are joined end to end. Find the cost of painting the resulting cuboid all around at the rate of ₹25 per 100 cm².
₹1,000
Each cube has a volume of 8,000 cm³, so the side length of each cube is ∛8000 = 20 cm. After joining the cubes, the cuboid has dimensions 20 × 20 × 40 cm. The surface area of the cuboid is:
Surface Area = 2 × (20 × 20 + 20 × 40 + 20 × 40) = 2 × (400 + 800 + 800) = 4000 cm²
The cost of painting = (4000/100) × 25 = ₹1,000.
Important Questions from Mensuration
In a circular garden of radius 15 m, a path of 2 m wide has to be made inside the garden at the rate of ₹ 24 per sq. m. The cost of making the path is: (Take π = \(\frac{22}{7}\) )
A hollow cylinder with outer radius 4 cm and height 2 cm is made up of 1 cm thick metal sheet. What is the volume of metal used? (Take π = \(\frac{22}{7}\))
The length and breadth of a rectangular field are in the ratio 4 : 3. If the cost of cultivating the field at ₹2 per m 2is ₹600, then the length of the field is:
A cylindrical tank has a capacity of 5632 m3. If the diameter of its base is 8 m, what is the depth of the cylindrical tank? (Use π = \(\frac{22}{7}\))
Find the surface area of a sphere whose diameter is equal to 28 cm.
