RD Sharma Class 8 Solutions Chapter 21 - Mensuration II - Volumes Surface Area Cuboid and A Cube (Ex 21.2) Exercise 21.2 - Free PDF
FAQs on RD Sharma Class 8 Solutions Chapter 21 Mensuration II - Volumes Surface Area of Cuboid and Cube Exercise 21.2
1. What is a cuboid and how is it different from a rectangle?
Cuboid is a polygon represented in three-dimensional format on a plane surface. It has 6 surface areas similar to that of a rectangle. The rectangle is a quadrilateral with four sides, four angles and four vertices. The opposite sides of a rectangle are equal and all angles measure 90 degrees. A cuboid is a 3-D representation of a rectangle with length, breadth and perpendicular height. The rectangle is a 2D figure with only length and breadth. Gift boxes are the best example of a cuboid and a cot is the best example of a rectangle.
2. What is the formula to find the total surface area of a cuboid and cube?
Cuboid has 6 surface areas, 8 vertices and 12 edges. RD Sharma chapter 21 class 8 has many problems related to finding out the total surface area of a cuboid and mentions the formula for it:
The total surface area of a cuboid is represented by T.S.A.
T.S.A. of cuboid = 2(lb + bh +lh)
where,
h = perpendicular height from the base
l = length of the cuboid
b = breadth of the cuboid
Similarly, the total surface area of a cube is represented by T.S.A.
T.S.A of cube = 6a2
All the sides of a cube are equal as a cube is a 3D representation of a square
Here a = length of the side
3. What is the formula to find out the lateral surface area of a cuboid and its perimeter?
Lateral surface area is represented by L.S.A
L.S.A of cuboid = 2h(l + b)
l = length ; b= breadth; h = perpendicular height
Similarly, the perimeter of a cuboid is represented by P
P = 4(l+b+h)
l= length; b = breadth, h = perpendicular height
4. What is the formula to find out the volume of a cuboid and a cube?
Cuboid and cubes are polygons represented in three-dimensional format on a plane surface. RD Sharma chapter 21 class 8 has many problems related to finding out the volume of a cuboid and mentions the formula for the same:
The volume of the cuboid is represented by V
V = l x b x h
l= length, b= breadth, h= height
Similarly, the volume of a cube represented by V
V = a3
a= length of side .