Ex 11.1, 12 - Chapter 11 Class 10 Areas related to Circles

Last updated at August 14, 2026 by

Ex 11.1, 12 - To warn ships for underwater rocks, a lighthouse - Ex 11.1

part 2 - Ex 11.1, 12 - Ex 11.1 - Serial order wise - Chapter 11 Class 10 Areas related to Circles

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Ex 11.1, 12 To warn ships for underwater rocks, a lighthouse spreads a red coloured light over a sector of angle 80ยฐ to a distance of 16.5 km. Find the area of the sea over which the ships are warned. (Use ฯ€= 3.14) Radius (r) = 16.5 km And, ๐œฝ=๐Ÿ–๐ŸŽยฐ Area over which ships are warned = Area of sector with angle 80ยฐ = ๐œƒ/(360ยฐ)ร—๐œ‹๐‘Ÿ2 = (๐Ÿ–๐ŸŽยฐ)/๐Ÿ‘๐Ÿ”๐ŸŽร—๐Ÿ๐Ÿ/๐Ÿ• ร— (๐Ÿ๐Ÿ”.๐Ÿ“)๐Ÿ = 80/360ร—22/7 ร— 16.5 ร— 16.5 = 2/9ร—22/7ร—165/10ร—165/10 = 189.97 km2 Hence, Area of sea cover = 189.97 km2

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