Question 5 - Volume Of Cylinder - Chapter 11 Class 9 Surface Areas and Volumes

Transcript

Question 5 It costs Rs 2200 to paint the inner curved surface of a cylindrical vessel 10 m deep. If the cost of painting is at the rate of Rs 20 per m2, find (i) inner curved surface area of the vessel, Cost of painting = Inner curved surface area Rate of painting Rs 2200 = Inner curved surface area 20 2200/20 = Inner curved surface area Inner curved surface area = 2200/20 Inner curved surface area = 110 Therefore, inner curved surface area of vessel = 110 m2 Question 5 (ii) radius of the base, Let radius of cylinder be r Height = h = 10 m We know that Curved surface area of cylinder = 110 m2 2 = 110 2 22/7 r 10 = 110 r = (110 7)/(2 22 10) r = 7/4 r = 1.75 m Question 5 (iii) capacity of the vessel. We know that Height = h = 10 m Radius = r = 1.75 m = 7/4 m Capacity of the vessel = volume = r2h = (22/7 7/4 7/4 10) m3 = (22 1/4 7/4 10) m3 = 96.25 m3