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# Find what length of canvas 2 m in width is required to make a conical tent 20 m in diameter and 42 m in slant height allowing 10% for folds and the stitching. Also find the cost of the canvas at the rate of Rs 80 per metre.

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ICSE Board Question Based on Mensuration Chapter of M.L Aggarwal for class10
In this question width,diameter and slant height of a conical tent is given.
Also find the cost of the canvas at the rate of Rs 80 per metre.
This is the Question Number 14, Exercise 17.2 of M.L Aggarwal.

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1. Given diameter of the conical tent, d = 20 m

radius, r = d/2 = 20/2 = 10 m

Slant height, = 42 m

Curved surface area of the conical tent = πrl

= (22/7)×10×42

= 22×10×6

= 1320 m2

So the area of canvas required is 1320 m2.

Since 10% of this area is used for folds and stitches, actual cloth needed = 1320+ 10% of 1320

= 1320 + (10/100)×1320

= 1320+132

= 1452 m2

Width of the cloth = 2m

Length of the cloth = Area/width = 1452/2 = 726 m

Cost of canvas = Rs.80 per metre.

Total cost = 80×726 = Rs. 58080

Hence the total cost of the canvas is Rs. 58080.

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