10 cylindrical pillars of a building have to be painted. The diameter of each pillar is 70 cm and the height is 4m. What is the co

2 thoughts on “10 cylindrical pillars of a building have to be painted. The diameter of each pillar is 70 cm and the height is 4m. What is the co”

1. ANSWER:

   Given:

   • 10 cylindrical pillars
   • Diameter of each pillar = 70cm = 0.7m
   • Height of each pillar = 4m
   • Cost of painting per sq. metre = Rs 10

   To Find:

   • Cost of painting all 10 pillars

   Diagram:

   [tex] \setlength{\unitlength}{1mm}\begin{picture}(5,5)\thicklines\multiput(-0.5,-1)(26,0){2}{\line(0,1){40}}\multiput(12.5,-1)(0,3.2){13}{\line(0,1){1.6}}\multiput(12.5,-1)(0,40){2}{\multiput(0,0)(2,0){7}{\line(1,0){1}}}\multiput(0,0)(0,40){2}{\qbezier(1,0)(12,3)(24,0)\qbezier(1,0)(-2,-1)(1,-2)\qbezier(24,0)(27,-1)(24,-2)\qbezier(1,-2)(12,-5)(24,-2)}\multiput(16,2)(0,32){2}{\sf{0.35m}}\put(7,17.5){\sf{4m}}\end{picture}[/tex]

   Concept(Approach used):

   We are given that, the cylindrical pillars are to be painted. So, we will first find the Curved(or Lateral) Surface Area of 1 pillar. Then we will multiply it with the cost of painting. After that we will multiply the cost of painting 1 pillar with 10 so that we get the total cost, which will be our answer.

   So, lets begin!!

   Solution:

   We are given that the diameter of the pillars is 70cm(0.7m).

   So,

   ⇒ radius(r) = diameter/2 = 0.7m/2 = 0.35m.

   And,

   ⇒ height(h) = 4m

   Hence,

   ⇒ Curved Surface Area of a cylinder = 2πrh

   Here, r = 0.35m, h = 4m, π = 22/7

   Therefore,

   ⇒ CSA of 1 cylindrical pillar = 2 * 22/7 * 0.35 * 4

   ⇒ CSA of 1 cylindrical pillar = 2 * 22/7 * 35/100 * 4

   ⇒ CSA of 1 cylindrical pillar = 2 * 22 * 5/100 * 4

   ⇒ CSA = 22 * 1/10 * 4

   ⇒ CSA of 1 cylindrical pillar = 8.8m²

   Now,

   ⇒ Cost of painting 1m² = Rs 10

   ⇒ Cost of painting 8.8m² = Rs 10 * 8.8

   ⇒ Cost of painting 8.8m² = Rs 88

   Hence,

   ⇒ Cost of painting 1 cylindrical pillar = Rs 88

   Now,

   ⇒ Cost of painting 10 cylindrical pillars = Rs 88 * 10

   ⇒ Cost of painting 10 cylindrical pillars = Rs 880

   Hence, cost of painting 10 cylindrical pillars is Rs 880.

   Formula Used:

   • Curved Surface Area of a cylinder = 2πrh

   Learn More:

   • Curved Surface Area of a cylinder = 2πrh
   • Total Surface Area of a cylinder = 2πrh + πr²
   • Volume of a cylinder = πr²h

   Reply

2. Answer:

   Answer –880

   Explanation :

   CSA of 10 cyc= 10*2πrh

   = 2 * 22/7 * 35/100 * 4

   = 44*35*4/(700)

   = 10*176*35/700

   = 176*35 /70

   Cost = 10*176*35/70

   = 880rs

   Reply