NCERT Solutions for Class 10 Maths Chapter 12 Exercise 12.1

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CBSE X Related Questions

1.

The lengths of 40 leaves of a plant are measured correct to the nearest millimetre, and the data obtained is represented in the following table :

Length (in mm)

Number of leaves

118 - 126

3

127 - 135 

5

136 - 144

9

145 - 153

12

154 - 162

5

163 - 171

4

172 - 180

2

Find the median length of the leaves. 
(Hint : The data needs to be converted to continuous classes for finding the median, since the formula assumes continuous classes. The classes then change to 117.5 - 126.5, 126.5 - 135.5, . . ., 171.5 - 180.5.)

      2.
      Which of the following are APs? If they form an AP, find the common difference d and write three more terms.
      (i) 2, 4, 8, 16, . . . .
      (ii) \(2, \frac{5}{2},3,\frac{7}{2}\), . . . .
      (iii) – 1.2, – 3.2, – 5.2, – 7.2, . . . .
      (iv) – 10, – 6, – 2, 2, . . .
      (v) 3, \(3 + \sqrt{2} , 3 + 3\sqrt{2} , 3 + 3 \sqrt{2}\) . . . .
      (vi) 0.2, 0.22, 0.222, 0.2222, . . . .
      (vii) 0, – 4, – 8, –12, . . . .
      (viii) \(\frac{-1}{2}, \frac{-1}{2}, \frac{-1}{2}, \frac{-1}{2}\), . . . .
      (ix) 1, 3, 9, 27, . . . .
      (x) a, 2a, 3a, 4a, . . . .
      (xi) a, \(a^2, a^3, a^4,\)  . . . .
      (xii) \(\sqrt{2}, \sqrt{8} , \sqrt{18} , \sqrt {32}\) . . . .
      (xiii) \(\sqrt {3}, \sqrt {6}, \sqrt {9} , \sqrt {12}\) . . . . .
      (xiv) \(1^2 , 3^2 , 5^2 , 7^2\), . . . .
      (xv) \(1^2 , 5^2, 7^2, 7^3\), . . . .

          3.
          An umbrella has 8 ribs which are equally spaced (see Fig. 11.10). Assuming umbrella to be a flat circle of radius 45 cm, find the area between the two consecutive ribs of the umbrella.
          An umbrella has 8 ribs which are equally spaced

              4.
              A vessel is in the form of an inverted cone. Its height is 8 cm and the radius of its top, which is open, is 5 cm. It is filled with water up to the brim. When lead shots, each of which is a sphere of radius 0.5 cm are dropped into the vessel, one-fourth of the water flows out. Find the number of lead shots dropped in the vessel.

                  5.

                  Prove the following identities, where the angles involved are acute angles for which the expressions are defined:\(\frac{(\text{1 + tan² A})}{(\text{1 + cot² A})} = (\frac{\text{1 - tan A }}{\text{ 1 - cot A}})^²= \text{tan² A}\)

                      6.

                      Solve the following pair of linear equations by the substitution method. 
                      (i) x + y = 14 
                          x – y = 4   

                      (ii) s – t = 3 
                          \(\frac{s}{3} + \frac{t}{2}\) =6 

                      (iii) 3x – y = 3 
                            9x – 3y = 9

                      (iv) 0.2x + 0.3y = 1.3 
                           0.4x + 0.5y = 2.3 

                      (v)\(\sqrt2x\) + \(\sqrt3y\)=0
                          \(\sqrt3x\) - \(\sqrt8y\) = 0

                      (vi) \(\frac{3x}{2} - \frac{5y}{3}\) =-2,
                          \(\frac{ x}{3} + \frac{y}{2}\) = \(\frac{ 13}{6}\)

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