Question

a conical tank of radius 7m and height 24m is to be made find the cost of 5m wide cloth required at the rate 50 rupees per meter

Answer 1

Let the slant height of the cone be 'l' meters.
height = 24 m and radius = 7 m. 
Then according to the question.
l² = h² + r²
l² = 24² + 7²
l² = 576 + 49 
l² = 625
l = √625
l = 25 m
So, the slant height of the cone is 25 m.
Now, 
Curved Surface Area of the cone = πrl
= 22/7*7*25
CSA = 550 sq m
Now, length of the cloth used = Area/ width of the cloth
= 550/5
Length of the cloth used = 110 m 
Cost of cloth = Rs. 50per meter
Total cost of clothe used = 110*50
= Rs. 5500

Answer 2

Answer:

let the slant of height of a cone be “l”

metre

height = 24m. and radius = 7m

the A/Q

l^2= h^2 + r^2

l^2 = 24^2 + 7^2

l^2 = 625

l. = √625

l. = 25

so the slant of height of cone is 25

now

CSA of a cone = πrl

22/7×7/25

550sqm

now length = area/ width of length

550/5

110

cost of cloths = RS 50 per metre

total cost of cloths used 110 × 50

5500

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