the circular photo frame and outer radius 20 cm and radius 18 cm find the width of the frame around the photo also find the cost of painting it with a metallic colour at the rate of ₹ 0.7 per cm . (take π=22/7
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Step-by-step explanation:
(i) width of the frame = outer radius(R) - inner radius(r)
= 20-18
=2cm
(ii) area of the frame = area of the whole photo(with frame) - area of the photo
= π(R²-r²)
=22(20²-18²)/7
=1672/7 cm²
painting cost rate = ₹0.7/ cm²
so, total cost = ₹1672*0.7/7
= ₹167.2
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