Question

A conical heap of water has a diameter 42m and height 20 m. find the area of the plastic to cover the heap to protect it from rain. if the rate of plastic is Rs.5/m^2, find the cost of plastic.​

Answer 1

Answer:

Total cost of plastic is Rs. 9570

Step-by-step explanation:

Given: Diameter of conical heap,d = 42 m

           Height of conical heap,h = 20 m

           Rate of plastic of 1 m² = Rs. 5

To find: Cost of Plastic

Area of Plastic = Area of conical heap = Curved surface area of cone

Area of plastic = $\pi rl$

radius of heap, r =  $\frac{42}{2}$  = 21 m

slant height of heap, l = $\sqrt{r^2+h^2}$

                                     =  $\sqrt{21^2+20^2}$

                                     =  $\sqrt{441+400}$

                                     =  $\sqrt{841}$

                                     =  29 m

⇒ Area of plastic =  $\frac{22}{7}\times21\times29$

                            =  $22\times3\times29$

                            =  $1914\:m^2$

Cost of Plastic of 1914 m² = 1914 × 5

                                          = Rs. 9570

Therefore, Total cost of plastic is Rs. 9570

Answer 2

Step-by-step explanation:

Answer:

Total cost of plastic is Rs. 9570

Step-by-step explanation:

Given: Diameter of conical heap,d = 42 m

Height of conical heap,h = 20 m

Rate of plastic of 1 m² = Rs. 5

To find: Cost of Plastic

Area of Plastic = Area of conical heap = Curved surface area of cone

Area of plastic = \pi rlπrl

radius of heap, r = \frac{42}{2}

2

42

= 21 m

slant height of heap, l = \sqrt{r^2+h^2}

r

2

+h

2

= \sqrt{21^2+20^2}

21

2

+20

2

= \sqrt{441+400}

441+400

= \sqrt{841}

841

= 29 m

⇒ Area of plastic = \frac{22}{7}\times21\times29

7

22

×21×29

= 22\times3\times2922×3×29

= 1914\:m^21914m

2

Cost of Plastic of 1914 m² = 1914 × 5

= Rs. 9570

Therefore, Total cost of plastic is Rs. 9570