Diameter of each pillar = 50 cmHeight of each pillar = 4 MNUMBER of pillars = 10To Find:-The cost of painting 10 pillars at the rate of Rs.14 per sq.metre.Solution:-Dimensions of pillar is given as:-Diameter = 50 cmWe know,Radius = Diameter/2⇒ Radius = 50/2⇒ Radius = 25 cmLet us convert cm into m by dividing the unit by 100.∴ Radius = 25 cm = 25/100 = 0.25 MNOW,Since pillar is attached to the ceiling on the TOP and to the ground on the bottom, we need to find the lateral surface area of the cylinder.We know,Lateral Surface Area of cylinder = 2πrhHence,LSA of one pillar = 2 × 22/7 × 0.25 × 4⇒ LSA of one pillar = 2 × 22/7 × 25/100 × 4⇒ LSA of one pillar = 2 × 22/7 × 1/4 × 4⇒ LSA of one pillar = 44/7 m²∴ Lateral Surface Area of one pillar is 44/7 m²Now,Since LSA of one pillar is 44/7 m²Hence,LSA of 10 such pillars = 44/7 × 10⇒ LSA of 10 pillar = 440/7 m²Now,Cost of painting 1 m² = ₹14Therefore,Cost of painting 440/7 m² = 440/7 × 14⇒ Cost of painting 440/7 m² = 440 × 2⇒ Cost of painting 440/7 m² = ₹880 ∴ The cost of painting 10 pillars is ₹880.________________________________Extra Information!!Other formulas related to cylinder:-Volume of cylinder = πr²h cu.unitsTSA of cylinder = 2πr(r + h) sq.unitsRemember:- TSA stands for Total Surface Area.________________________________