Advertisements
Advertisements
प्रश्न
Each edge of a cube is increased by 50%. Find the percentage increase in the surface area of the cube.
Advertisements
उत्तर
`"Let d be the edge of the cube"`
`∴surface area of cube= 6xxa^2`
i.e, `S_1=6a^2`
According to problem when edge increased by 50% then the new edge becomes
`=a+50/100xxa`
`=3/2a`
`"New surface area becomes" =6xx(3/2a)^2`
i.e.,`=6xx9/4a^2`
`s_2=27/2a^2`
∴Increased surface Area = `27/2a^2-6a^2`
`=15/2a^2`
So, increase in surface area `(15/2a^2)/6a^2`
`=15/12xx100`
`=125%`
APPEARS IN
संबंधित प्रश्न
The floor of a rectangular hall has a perimeter 250 m. If the cost of panting the four walls at the rate of Rs.10 per m2 is Rs.15000, find the height of the hall.
[Hint: Area of the four walls = Lateral surface area.]
A closed iron tank 12 m long, 9 m wide and 4 m deep is to be made. Determine the cost of iron sheet used at the rate of Rs. 5 per metre sheet, sheet being 2 m wide.
Find the height of a cuboid of volume 100 cm3, whose length and breadth are 5 cm and 4 cm respectively.
The dimensions of an oil tin are 26 cm × 26 cm × 45 cm. Find the area of the tin sheet required for making 20 such tins. If 1 square metre of the tin sheet costs Rs 10, find the cost of tin sheet used for these 20 tins.
A classroom is 7 m long, 6 m broad and 3.5 m high. Doors and windows occupy an area of 17 m2. What is the cost of white-washing the walls at the rate of Rs 1.50 per m2.
If the areas of the adjacent faces of a rectangular block are in the ratio 2 : 3 : 4 and its volume is 9000 cm3, then the length of the shortest edge is
Find the volume of wood required to make a closed box of external dimensions 80 cm, 75 cm, and 60 cm, the thickness of walls of the box being 2 cm throughout.
The total surface area of a cylinder is 6512 cm2 and the circumference of its bases is 88 cm. Find:
(i) its radius
(ii) its volume
If radii of two cylinders are in the ratio 4 : 3 and their heights are in the ratio 5: 6, find the ratio of their curved surfaces.
Find the volume of wood used in making a closed box 22 cm by 18 cm by 14 cm, using a 1 cm thick wood. Also, find the cost of wood required to make the box at the rate of Rs. 5 per cm³ How many cubes of side 2 cm can be placed in the box?
