Question

Along a path, 25 conical pillars are constructed. Each pillar has radius 15cm and height 20cm. Find the total cost of painting at the rate of Rupees 50 per centimeter square(take pie =3.14)

Answer 1

Answer:

5887500 cm²

Step-by-step explanation:

Given, radius of conical pillar r = 15 cm.

Given, height of conical pillar,h = 20 cm.

We know that slant height(l) = √r² + h²

                                               = √15² + 20²

                                               = √225 + 400

                                               = √625

                                               = 25 cm.

We know that curved surface area of pillar = πrl

= (3.14) * (15) * (25)

= 1177.5 cm².

Then,curved surface area of 100 conical pillars = 100 * 1177.5

= 117750 cm².

∴ cost of paining per cm² = 50

Cost of painting 117857 cm² = 50 * 117750

                                               = 5887500 cm².

Hope it helps!

Answer 2

Answer: Rs. 1,471,875  

Step-by-step explanation:

Given , the radius of pillar = 15cm

Given , the height of pillar is = 20 cm

To find curved surface area of cone, we have to find slant height

So we use pythagoras theorem,

H²= p²+ b²

     =15² + 20²

     = 225 + 200

     =625

      =√625

     = 25

So, the slant height (l)  is 25 cm

Now, the curved surface area of cone is πrl

       putting the value of radius and slant height

      = 3.14×15×25

      = 1177.5 cm²

total cost of painting pillars = 50× 1177.5

                                          =58,875

cost of painting 25 conical pillar = 25× 58,875

                                                  = 1,471,875