Selina Solutions for Class 10 maths Chapter 20 Cylinder, Cone and Sphere (Surface Area and Volume)
Concise Selina Solutions for Class 10 maths Chapter 20 Cylinder, Cone and Sphere (Surface Area and Volume)
Poster tube and solar tank both these objects are in the shape of a cylinder. Some other objects like Tent, Joker's cap, funnel etc. are in the shape of a cone. In this topic, we shall learn as to how to find the area and capacity of cylindrical and conical objects.
Surface Area of Cylinders. To find the surface area of a cylinder, add the surface area of each end plus the surface area of the side. Each end is a circle, so the surface area of each end is pi * r2, where r is the radius of the end. There are two ends, so their combined surface area is 2 pi * r2.
Surface area to volume ratio can be found easily for several simple shapes, like for example, a cube or a sphere. The volume of a sphere is V= 4*Pi*R*R*R/3. So for a sphere, the ratio of surface area to volume is given by S/V = 3/R.
A cone is a three-dimensional geometric shape that tapers smoothly from a flat base to a point called the apex or vertex. A cone is a solid that has a circular base and a single vertex. If the vertex is over the centre of the base, it is called a right cone. If it is not, it is called an oblique cone. An object that is shaped like a cone is said to be 'conical'.