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Question 5: 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 the greater lateral surface area and by how much? (ii) Which…
Read MoreQuestion 4: The paint in a certain container is sufficient to paint an area equal to 9.375m2. How many bricks of dimensions 22.5 cm × 10 cm × 7.5 cm can be painted out of this container? Question 3 Question…
Read MoreQuestion 3: 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. [Hint :…
Read MoreQuestion 2: 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…
Read MoreQuestion 1: 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…
Read MoreExample 2: Hameed has built a cubical water tank with lid for his house, with each outer edge 1.5 m long. He gets the outer surface of the tank excluding the base, covered with square tiles of side 25 cm…
Read MoreExample 1: Mary wants to decorate her Christmas tree. She wants to place the tree on a wooden box covered with coloured paper with picture of Santa Claus on it (see Fig. 13.4). She must know the exact quantity of…
Read MoreDerivation of Heron’s formula: This formula has been named after the Egyptian mathematician Heron. This famous formula is about finding the area of a triangle when its all three sides are given. It is derived from the formula of area…
Read MoreExample 6: Sanya has a piece of land which is in the shape of a rhombus (see Fig. 12.13). She wants her one daughter and one son to work on the land and produce different crops. She divided the land…
Read MoreExample 5: Students of a school staged a rally for cleanliness campaign. They walked through the lanes in two groups. One group walked through the lanes AB, BC and CA; while the other through AC, CD and DA (see Fig.…
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