Question 1. A brick measures 30 cm × 10 cm × cm. How many bricks will be required for a wall 30 m long, 2 m high and (3/4)m thick?
Hint: Volume of wall (cuboid) = 30 × 2 × (3/4) m^{3 }= 45 m^{3}
Volume of 1 brick =
∴ Required number of bricks =
Question 2. The surface area of a cube is m^{2}. Find its volume.
Hint: Total S.A. = 6(side)^{2} ⇒ side^{2} = ÷ 6
∴ Volume = (side)^{3 } =
Question 3. A hemispherical tank is emptied by a pipe at the rate of 5 litres per minute. How long will it take to halfempty the tank if it is metre in diameter. [Take π = (22/7) and 1l = 1000 cm]^{3}
Hint: Radius
Volume of the hemisphere = (1/2) (volume of a sphere) =
Volume to be emptied
∵ 5 litres is emptied in 1 minute
48 videos378 docs65 tests

1. What is the formula for finding the surface area of a cube? 
2. How do you calculate the total surface area of a cylinder? 
3. What is the formula for finding the volume of a sphere? 
4. How can I find the surface area of a cone? 
5. What is the formula for calculating the volume of a rectangular prism? 
48 videos378 docs65 tests


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