Question

8) A hollow hemisphere of radius 50 cm is painted from the inner side at the rate of 10 paise/cm. Find
the expenditure. (pi = 3.14)​

Answer 1

Given:

The radius of the hollow hemisphere, r = 50 cm

The cost of painting the hollow hemisphere from the inner side is 10 paise/cm

To find:

The expenditure

Solution:

We have to paint the hollow hemisphere from inside so we will first find the curved surface area of the hemisphere.

The formula of the curved surface area of the hemisphere is given as,

$\boxed{\boxed{\bold{C.S.A.\:of\:a\:hemisphere\:=\:2 \pi r^2}}}$

Substituting the value of r = 50 cm  and pi = 3.14 in the above formula, we get

$C.S.A.\:of\:the\: hollow\:hemisphere\:=\:2 \times 3.14\times 50^2 = 2 \times 3.14\times 2500 = 15700 \:cm^2$

Now,

If the cost of painting per cm of the hollow hemisphere = Rs. 0.10

Then,

The cost of painting 15700 cm² of the hollow hemisphere will be,

= Rs. 0.10 × 15700 cm²

= Rs. 1570

Thus, the expenditure is Rs. 1570.

----------------------------------------------------------------------------------------------------

Also View:

The internal and external radii of a hollow hemispherical vessel are 15 cm and 16 cm respectively. The cost of painting 1 cm² of the surface is Rs.7. Find the total cost of painting the vessel all over. (ignore the area of edges)

https://brainly.in/question/11768556

In a building there are 24 cylindrical pillars. The radius of each pillar is 28 cm and height is 4 m. Find the total cost of painting the curved surface area of all pillars at the rate of ₹8 per metre square.

https://brainly.in/question/256920

A building is in the form of a hollow hemisphere of outer radius 100 m and thickness of wallis 1 m. If cost of painting 1 sq.m. ia Rs. 5 then total cost of painting both the outer and innerwalls of the building is​?

https://brainly.in/question/11750490