 # Surface Area: Cubes, Cuboids

Class 9 NCERT Exercise 13.1 Solution and Video
1. #### Surface area of cuboid

A plastic box 1.5 m long, 1.25 m wide and 65 cm deep is to be made. It is opened at the top. Ignoring the thickness of the plastic sheet, determine:

(i)  The area of the sheet required for making the box.
(ii) The cost of sheet for it, if a sheet measuring 1 m2 costs Rs 20.

2. #### Lateral surface area & base area of cuboid

The length, breadth and height of a room are 5 m, 4 m and 3 m respectively. Find the cost of white washing the walls of the room and the ceiling at the rate of Rs.7.50 per m2

3. #### Rectangle Perimeter, Lateral Surface Area of Cuboid

The floor of a rectangular hall has a perimeter 250 m. If the cost of painting the four walls at the rate of Rs.10 per m2 is Rs.15000, find the height of the hall.

4. #### Total Surface Area of Cuboid

The paint in a certain container is sufficient to paint an area equal to 9.375 m2. How many bricks of dimensions 22.5 cm x 10 cm x 7.5 cm can be painted out of this container?

5. #### Lateral & Total Surface Area: Cube & Cuboid

A cubical box has each edge 10 cm and another cuboidal box is 12.5 cm long, 10 cm wide and 8 cm high.

(i)  Which box has greater lateral surface area and by how much?
(ii) Which box has the smaller total surface area and by how much?

6. #### Total Surface Area of Cuboid

A small indoor greenhouse (herbarium) is made entirely of glass panes (including base) held together with tape. It is 30 cm long, 25 cm wide and 25 cm high.

(i)  What is the area of the glass?
(ii) How much of tape is needed for all the 12 edges?

7. #### Total Surface Area of Cuboids

Shanti Sweets Stall was placing an order for making cardboard boxes for packing their sweets. Two sizes of boxes were required. The bigger of dimensions 25 cm x 20 cm x 5 cm and the smaller of dimensions 15 cm x 12 cm x 5 cm. For all the overlaps, 5% of the total surface area is required extra. If the cost of the cardboard is Rs.4 for 1000 cm2, find the cost of cardboard required for supplying 250 boxes of each kind.

8. #### Lateral Surface Area & Base Area of Cuboid

Parveen wanted to make a temporary shelter for her car, by making a box-like structure, with tarpaulin that covers all the four sides and the top of the car (with the front face as a flap which can be rolled up). Assuming that the stitching margins are very small, and therefore negligible, how much tarpaulin would be required to make the shelter of height 2.5 m, with base dimensions 4 m x 3 m?