Advertisements
Advertisements
Question
Each edge of a cube is increased by 50%. Find the percentage increase in the surface area of the cube.
Advertisements
Solution
`"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
RELATED QUESTIONS
Find the lateral surface area and total surface area of a cuboid of length 80 cm, breadth 40 cm and height 20 cm.
Hameed has built a cubical water tank with lid for his house, with each other edge 1 .5 m long. He gets the outer surface of the tank excluding the base, covered with square tiles of side 25 cm. Find how much he would spend for the tiles, if the cost of tiles is Rs. 360 per dozen.
Find the weight of solid rectangular iron piece of size 50 cm × 40 cm × 10cm, if 1 cm3 of iron weighs 8 gm.
A cloassroom is 11 m long, 8 m wide and 5 m high. Find the sum of the areas of its floor and the four walls (including doors, windows, etc.)
A swimming pool is 20 m long 15 m wide and 3 m deep. Find the cost of repairing the floor and wall at the rate of Rs 25 per square metre.
The dimensions of a rectangular box are in the ratio of 2 : 3 : 4 and the difference between the cost of covering it with sheet of paper at the rates of Rs 8 and Rs 9.50 per m2 is Rs. 1248. Find the dimensions of the box.
If two cubes each of side 6 cm are joined face to face, then find the volume of the resulting cuboid.
If the volumes of two cubes are in the ratio 8: 1, then the ratio of their edges is
A closed rectangular box is made of wood of 1.5 cm thickness. The exterior length and breadth are respectively 78 cm and 19 cm, and the capacity of the box is 15 cubic decimeters. Calculate the exterior height of the box.
The ratio between the curved surface area and the total surface area of a cylinder is 1: 2. Find the ratio between the height and the radius of the cylinder.
