 Hello and welcome to the session. My name is Asha and I shall be helping you with the following question that says A cylindrical pillar is 50 cm in diameter and 3.5 m in height. Find the cost of painting the curved surface of the pillar at the rate of rupees 12 per meter square. So let's begin with the solution and here we are given First, the diameter of the pillar is equal to 50 cm. So this implies that radius of the pillar let us denoted by small r is equal to 50 cm divided by 2 that is equal to 25 cm. And since 1 cm is equal to 1 upon 100 meters therefore we have 25 upon 100 meters and this is equal to 1 upon 4 meters. So this is the radius of the pillar. Also we are given the height of the pillar is equal to 3.5 meters. Now we have to find the cost of painting the curved surface of the pillar at the rate of rupees 12.50 per meter square. So first let us find the curved surface area of the pillar and this is equal to 2 pi r h where r is the radius of the pillar and h is the height of the pillar. So let us denote the height of the pillar by h which is equal to 3.5 meters. So this is equal to 2 into 22 upon 7 into radius is 1 upon 4 into height is 3.5 meters square. Now 7 into 0.5 is 35, 22 is 4 and 2 into 11 is 22 so we have 5.5 meters square. So this is the curved surface area of the pillar. Now we are given the cost of painting 1 meter square is equal to rupees 12.50 therefore cost of painting 5.5 meters square is equal to rupees 12.50 into 5.5 and this gives rupees 68.75 thus the cost of painting the pillar at the rate of rupees 12.50 is rupees 68.75. This is our answer. Hope you have enjoyed it. Take care and bye.