# To warn ships for underwater rocks, a lighthouse spreads a red coloured light over a sector of angle 80° to a distance of 16.5 km.

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To warn ships for underwater rocks, a lighthouse spreads a red coloured light over asector of angle 80° to a distance of 16.5 km. Find the area of the sea over which the hips warned.[Use π = 3.14]

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It can be observed from the figure that the lighthouse spreads light across a sector of 80° in a circle of 16.5 km radius.

Area of sector OACB = 80o/360o x πr2

= 2/9 x 3.14 x 16.5 x 16.5

= 189.97 km2