Question

ICBSE 2010)
A milk container is made of metal sheet in the shape of frustum of a cone whose volume
Is 104 cm The radii of its lower and upper circular ends are 8 cm and
20 cm respectively. Find the cost of metal sheet used in making the container at the
rate of 31.40 per cm². (Use a = 22/7)
[CBSE 2010)
​

Answer 1

Answer:

55,232.6 rupees

Step-by-step explanation:

Upper radius (r) = 8 cm

Lower diameter (R)= 20 cm

The volume of frustum = 10459 3/7 cm³ = 10459.4285 cm³

Therefore height of frustum(h) = ?

Volume = π/3. h (R² + r² + R.r)

10459.4285 = π/3. h (20² + 8² + 160)

∴ h = 16.01 cm ≅ 16 cm

The surface area of container = π (R+r) √(R-r)² + h²

= π (20 + 8) √(12² + 16²)

≅  1759 cm²

the cost of metal sheet used in making the container at the rate of 31.40 per cm

= 31.40 * 1759

= 55,232.6

.....