# NCERT Class 9 Mathematics Surface Area and Volume Board Sample Problems

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Mensuration

It is branch of mathematics which is concerned about the measurement of length, area and Volume of plane and Solid figure

Perimeter

The perimeter of plane figure is defined as the length of the boundary

It units is same as that of length i.e.. m, cm, km

 1 Meter 10 Decimeter 100 centimeter 1 Decimeter 10 centimeter 100 millimeter 1 Km 10 Hectometer 100 Decameter 1 Decameter 10 meter 1000 centimeter

Surface Area or Area

The area of the plane figure is the surface enclosed by its boundary

It unit is square of length unit. i.e..

 1 square Meter 100 square Decimeter 10000 square centimeter 1 square Decimeter 100 square centimeter 10000 square millimeter 1 Hectare 100 square Decameter 10000 square meter 1 square myraimeter 100 square kilometer square meter

Volume

 1mL 1 Litre 1000 ml 1000 L 1 L

Surface Area

Surface Area and Volume of Cube and Cuboid

 Type Measurement Surface Area of Cuboid of Length L, Breadth B and Height H Lateral surface area of the cuboids Diagonal of the cuboids Volume of a cuboids Length of all 12 edges of the cuboids Surface Area of Cube of side L Lateral surface area of the cube Diagonal of the cube Volume of a cube

Surface Area and Volume of Right circular cylinder

 Radius The radius (r) of the circular base is called the radius of the cylinder Height The length of the axis of the cylinder is called the height (h) of the cylinder Lateral Surface The curved surface joining the two base of a right circular cylinder is called Lateral Surface.
 Type Measurement Curved or lateral Surface Area of cylinder Total surface area of cylinder Volume of Cylinder

Surface Area and Volume of Right circular cone

 Radius The radius (r) of the circular base is called the radius of the cone Height The length of the line segment joining the vertex to the centre of base is called the height (h) of the cone. Slant Height The length of the segment joining the vertex to any point on the circular edge of the base is called the slant height (L) of the cone. Lateral surface Area The curved surface joining the base and uppermost point of a right circular cone is called Lateral Surface
 Type Measurement Curved or lateral Surface Area of cone Total surface area of cone Volume of Cone

Surface Area and Volume of sphere and hemisphere

 Sphere A sphere can also be considered as a solid obtained on rotating a circle About its diameter Hemisphere A plane through the centre of the sphere divides the sphere into two equal parts, each of which is called a hemisphere Radius The radius of the circle by which it is formed Spherical Shell The difference of two solid concentric spheres is called a spherical shell Lateral Surface Area for Sphere Total surface area of the sphere Lateral Surface area of Hemisphere It is the curved surface area leaving the circular base
 Type Measurement Surface area of Sphere Volume of Sphere Curved Surface area of hemisphere Total Surface area of hemisphere Volume of hemisphere Volume of the spherical shell whose outer and inner radii and R ′ and ′ r ′ respectively

How the Surface area and Volume are determined

 Area of Circle The circumference of a circle is . This is the definition of (pi) . Divide the circle into many triangular segments. The area of the triangles is times the sum of their bases, (the circumference) , times their height, r. Surface Area of cylinderSurface Area of Cylinder This can be imagined as unwrapping the surface into a rectangle. Surface area of cone This can be achieved by divide the surface of the cone into its triangles, or the surface of the cone into many thin triangles. The area of the triangles is times the sum of their bases, p, times their height,