 Hello and welcome to the session. Let us discuss the following question. It says, A right circular cylinder just encloses a sphere of radius r. Find 1 surface area of the sphere, curved surface area of the cylinder and the ratio of the areas obtained in part 1 and part 2. To solve this question, we need to know the formula for surface area of sphere which is 4 pi r square and the curved surface area of cylinder. Curved surface area of cylinder is 2 pi r h where h is the height of the cylinder and r is the radius of the cylinder and here r is the radius of the sphere. So this knowledge will work as the idea. Let us now move on to the solution. In the first part, we have to find the surface area of the sphere. Now radius of the sphere given to us is r. So the surface area of sphere equal to 4 pi r square because the radius is r. In the second part of the question, we have to find the curved surface area of the cylinder and its formula is 2 pi r h. So we need to know the radius of the cylinder and height of the cylinder. Now we are given that the cylinder encloses the sphere. That is the radius of the sphere is same as the radius of the cylinder right. It is also the radius of the sphere. It is also the radius. This much is the radius and the total is the height of the cylinder. That means 2 r is the height of the cylinder. That is the diameter of the sphere is the height of the cylinder and the diameter of the sphere is 2 r because radius is r and we know that diameter is twice of the radius. So here radius of cylinder is r and the height of the cylinder is 2 r. So the curved surface area of cylinder 2 pi r h radius is r and h is 2 r. So the curved surface area is 4 pi r square. Now in the third part we have to find the ratio of the areas obtained in 1 and 2. So the ratio of the areas of the sphere and the curved surface area of the cylinder 4 pi r square is 2 4 pi r square which is equal to 4 pi r square upon 4 pi r square which is equal to 1 by 1. So the ratio is 1 is to 1. Hence the surface area of the sphere is 4 pi r square and curved surface area of cylinder is 4 pi r square and the ratio of the areas is 1 is to 1. So this completes the question, why for now take care and have a good day.