Numerical Problems with Answers, Solution | Mensuration | Maths - Student Activity Questions and Answers | 9th Maths : UNIT 7 : Mensuration
Chapter: 9th Maths : UNIT 7 : Mensuration
Student Activity Questions and Answers
If the length, breadth and height of a cuboid are l, b and h respectively. Then
(i) Total Surface Area = 2 (lb + bh + lh ) sq.units.
(ii) Lateral Surface Area = 2 (l+b)h sq.units.
If the side of a cube is a units, then,
(i) The Total Surface Area = 6a2 sq.units
(ii) The Lateral Surface Area = 4a2 sq.units
Thinking Corner: Can you get these formulae from the corresponding formula of Cuboid?
Note
The units of length, breadth and height should be same while calculating the volume of a cuboid.
A few important conversions :1 cm3 =1 ml, 1000 cm3=1 litre, 1m3 =1000 litres
THINKING CORNER
Each cuboid given below has the same volume 120 cm3. Can you find the missing dimensions?
Activity
Take some square sheets of paper / chart paper of given dimension 18 cm × 18 cm. Remove the squares of same sizes from each corner of the given square paper and fold up the flaps to make a open cuboidal box. Then tabulate the dimensions of each of the cuboidal boxes made. Also find the volume each time and complete the table. The side measures of corner squares that are to be removed is given in the table below.
Observe the above table and answer the following:
(i) What is the greatest possible volume? Volume: 9×9×9=729 cm3 / 18×18×18=5832 cm3
(ii) What is the side of the square that when removed produces the greatest volume? Side: 9cm / 18cm
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