VOLUME & SURFACE AREA OF CUBE & CUBOID BY MAYANK AGNIHOTRI
O VOLUME Space occupied by a 3-D object is called its Volume'. It is always measured in cubic unit like meter centimetre3, etc. SURFACE AREA Surface area of a 3-D object is the area of all of its surfaces together. Surface area is measured in square unit like cm2, m2, etc.
CUBOID A 3-D object having 6 rectangular faces is called a cuboid Volume of the cuboid lx b x h Curved surface area of the cuboid 2(1 + b)h Total surface area of the cuboid 2(lb + bh+ lh) - - Length of the diagonal of cuboid (d) V12 b2 + h2 Where, l Length, b Breadth and h height
CUBE A 3-D object having 6 equal faces i.e square faces is called a cube. Volume of the cube a3 .curved surface area of the cube 4a2 Total surface area of the cube 6a 2 - Length of the diagonal of cube (d) - av3 Where, a -edge of the cube
Questions Ques 1. Find the volume and curved surface area of cuboid, having dimensions 10 m x 8 m x 6 m. Given dimensions are l = 10 m, b = 8 m and h = 6 m. Volume of cuboid= lbh = 10 8 6 = 480 m3 Ans Curved surface area 2 Sol. b)h 2(10 8) x 6 36 x 6 216 m2 Ans Ques 2. A tank is in the form of a cuboid. It holds a maximum of 540 m3 water. If the tank is 8 m long 2 and 15 m wide, then how many meters deep must the water be when the tank is full? (1) 2 (2) 4.5 (3) 2.5 (4) 3 ICTET Sept 2016] So Given, volume of tank 540 m3, length of tank 8 m and breadth of tank -15 m golume .3 5402 x 180 m)- 360 m2 2 volume 3 I b h=8 15 h = 120h 360 3 m 120h 360 Hence, the water must be 3 m deep. 120
Ques 3. Ram want to build a solid cube of 15 cm side. How many pieces are required of 5 cm side? volume of Solid cube o/15cm side= 15'=15x 15x15=27 Ans Sol. Required number of pied1ISM144 Ans Required number of pieces- Volume of Solid cube of 5 cm side 53 5x5x5 Ans Ques 4. The surface area of a cube is 96 cm2. What is the length of its side? So. et length of side of cube be a cm. Then, according to the question Surface area of cube = 96cm2 6a2 96 a96 16 4 cm Ans
A cube has a volume 125 cm3. Area of its one face is (1) 25 cm2 ICTET Nov 2012] Ques 5. (2) 5 cm2 (2) 30 cm2 (4) 20 cm2 Sol. Let side of cube be a cm volume of cube-a 3 so, area of one face 52 25 cm2 Ans
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