What is Surface Area of Solid Figures Surface Area of any solid is the sum of the area of all its faces.
Surface Area of Cuboid Surface Area of cuboid =
2(lb + lh + bh) Where l= length, b = breadth and h = height of the cuboid.
Area of four walls of Cuboid Area of four walls of Cuboid =
2 (lh + bh) = 2h(l +b) Surface Area of Cube Surface area of a cube of side 'a' =
6a2 Also, lateral surface area of cube =
4a2 What is Volume The amount of space occupied by a three - dimensional object is called its volume.
Volume of Cuboid Volume of cuboid = l x b x h
Where l= length, b = breadth and h = height of the cuboid.
Volume of cube A cube is a cuboid in which length, breadth and height are all equal.
Therefore, substituting l = b= h with a in the volume of cuboid formula, we get
Volume of a cube = l x b x h = a
3 Volume of a cube of edge 'a' units = a
3 Sums Q1. A hall 8 m long, 6 m wide and 4 m high has three doors of size 1.5 m by 2m and four windows of size 1.2 m by 1 m. Find the cost of papering the walls if the wall paper is 80 cm wide and costs Rs. 6 per meter.
Solution :- here l = 8 m, b = 6m and h =4m
Therefore, the area of the walls of the hall
= lateral surface area
= 2h(l + b) = 2 x 4(8 + 6) m
2 = 112 m
2 The area of three doors
= 3 (1.5 x 2) m
2 = 9 m
2 The area of four windows
= 4 x (1.2 x 1)m
2 = 4.8 m
2 Therefore the area to be papered
= [112 - (9 + 4.8)] m
2 = [112 - 13.8] m
2 = 98.2 m
2 The width of the paper = 80 cm = 0.8 m
Therefore the length of paper required = 98.2 / 0.8 m = 122.75 m
The cost of papering the walls = Rs. 6 x 122.75 =Rs. 736.5