Ex 9.2

Ex 9.2, 1 (a)

Ex 9.2, 1 (b) Important

Ex 9.2, 1 (c)

Ex 9.2, 2 (a) Important

Ex 9.2, 2 (b) Important

Ex 9.2, 2 (c)

Ex 9.2, 3

Ex 9.2, 4 Important

Ex 9.2, 5 Important

Ex 9.2, 6

Ex 9.2, 7 Important

Ex 9.2, 8 You are here

Ex 9.2, 9 Important

Ex 9.2, 10 Important

Ex 9.2, 11

Ex 9.2, 12 Important

Ex 9.2, 13 Important

Ex 9.2, 14

Ex 9.2, 15

Ex 9.2, 16 Important

Ex 9.2, 17 Important

Last updated at April 16, 2024 by Teachoo

Ex 9.2, 8 Find the cost of polishing a circular table-top of diameter 1.6 m, if the rate of polishing is Rs 15/m2. (Take π = 3.14) Here, Area to be polished = Area of circular table top Diameter = 1.6 m Radius = r = 𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟/2 = (𝟏.𝟔)/𝟐 = 16/(2 × 10) Area of table top = 𝜋r2 = 3.14 × (𝟖/𝟏𝟎)^𝟐 = 314/100 × 8/10 × 8/10 = (𝟑𝟏𝟒 × 𝟔𝟒)/𝟏𝟎𝟎𝟎𝟎 = 20096/10000 = 2.0096 m2 Now, Cost of polishing 1 m2 area = Rs 15 Cost of polishing 2.0096 m2 area = Rs 15 × 2.0096 = Rs 15 × 𝟐𝟎𝟎𝟗𝟔/𝟏𝟎𝟎𝟎𝟎 = Rs 3 × 20096/2000 = Rs 3 × 𝟏𝟎𝟎𝟒𝟖/𝟏𝟎𝟎𝟎 = Rs 30144/1000 = Rs 30.144 = Rs 30.14 (approx.) ∴ It will cost Rs 30.14 (approx.) to polish the table top