Samacheer Kalvi 9th Maths Solutions Chapter 2 Real Numbers Ex 2.9
Samacheer Kalvi 9th Maths Solutions Chapter 2 Real Numbers Ex 2.9
Tamilnadu Samacheer Kalvi 9th Maths Solutions Chapter 2 Real Numbers Ex 2.9
Multiple Choice Questions :
Question 1.
If n is a natural number then √n is
(1) always a natural number
(2) always an irrational number
(3) always a rational number
(4) may be rational or irrational
Solution:
(4) may be rational or irrational
Question 2.
Which of the following is not true?
(1) Every rational number is a real number.
(2) Every integer is a rational number.
(3) Every real number is an irrational number.
(4) Every natural number is a whole number.
Solution:
(3) Every real number is an irrational number
Hint:
Real numbers contain rationals and irrationals.
Question 3.
Which one of the following, regarding sum of two irrational numbers, is true?
(1) always an irrational number
(2) may be a rational or irrational number.
(3) always a rational number
(4) always an integer.
Solution:
(2) may be a rational or irrational number
Question 4.
Which one of the following has a terminating decimal expansion?
Question 9.
Find the odd one out of the following.
Question 20.
The length and breadth of a rectangular plot are 5 x 105 and 4 x 104 metres respectively. Its area is .
(1) 9 × 101 m2
(2) 9 × 109 m2
(3) 2 × 1010 m2
(4) 20 × 1020 m2
Solution:
(3) 2 × 1010 m2
Hint:
l = 5 × 105 metres; b = 4 × 104 metres
∴ Area = l × b = 5 x 105 × 4 × 104
= 20 × 105+4= 20 × 109= 2.0 × 101 × 109 = 2 × 1010m2
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