# HBSE Class 9 Maths Question Paper 2021 Answer Key

HBSE Class 9 Maths Question Paper 2021 Answer Key

HBSE Class 9 Maths Previous Year Question Paper with Answer. HBSE Board Solved Question Paper Class 9 Maths 2021. HBSE 9th Question Paper Download 2021. HBSE Class 9 Maths Paper Solution 2021. Haryana Board Class 9th Maths Question Paper 2021 Pdf Download with Answer.

1.(1) Which of the following is not a rational number ?

(A) √2

(B) 0

(C) √4

(D) √-16

Ans. (A) √2

(2) The p/q form of 0.47 (bar) is …………

Ans. 47/(100-1) = 47/99

(3) Find one rational number between 3 and 4.

Ans. 3.5 (infinite rational numbers between 3 & 4)

(4) Which of the following number is not in between 4/5 and 9/5 ?

(A) 3/5

(B) 5/5

(C) 6/5

(D) 8/5

Ans. (A) 3/5 = 0.6  (4/5 = 0.8 and 9/5 = 1.8)

(5) The coefficient of x² in 2 – x² + x³ is ………….

Ans. -1

(6) Factors of 4y² – 4y + 1 is :

(A) (2y + 1)²

(B) (4y – 1)²

(C) (2y – 1)²

(D) (2y – 2)²

Ans. (C) (2y – 1)²

4y² – 4y + 1 = (2y)² – 2(2y)(1) + 1² = (2y – 1)²

(7) Factors of 27 – 125a³ – 135a + 225a² is :

(A) (3 + 5a)²

(B) (3a + 5)³

(C) (3a – 5)²

(D) (3 – 5a)³

Ans. (D) (3 – 5a)³

Using formula, a³ – b³ – 3ab(a – b) = (a – b)³

(3 – 5a)³ = 27 – 125a³ – 135a + 225a²

(8) Zero of p(x) = 3x + 1 is …………

Ans.

3x + 1 = 0

3x = -1

x = – 1/3

Zero is -1/3

(9) What is product of (x + 4)(x + 10) ?

Ans. (x + 4)(x + 10) = x² + 10x + 4x + 40 = x² + 14x + 40

(10) What is solution of (2x + 1) = x + 3 ?

Ans.

2x + 1 = x + 3

2x – x = 3 – 1

x = 2

(11) The solution of equation x − 2y = 4 is :

(A) (0, 2)

(B) (4, 0)

(C) (1, 1)

(D) (2, 0)

Ans. (B) (4, 0)

x – 2y = 4

4 – 2(0) = 4

4 – 0 = 4

4 = 4  (L.H.S = R.H.S)

(12) Point (4, 1) satisfies to which equation of line ?

(A) x + 2y = 5

(B) x + 2y = −6

(C) x + 2y = 6

(D) x + 2y = 16

Ans. (C) x + 2y = 6

4 + 2(1) = 6

4 + 2 = 6

6 = 6  (L.H.S = R.H.S)

(13) Possible dimensions of Cuboid whose volume 3x² – 12x is :

(A) 3, x, x + 4

(B) 3, x – 4, x

(C) -3, -x, -x – 4

(D) None of these

Ans. (B) 3, x-4, x

3x² – 12x = 3x(x-4)

(14) Point (5, −7) lies in which Quadrant ?

(15) The point (0, 0) where x-axis and y-axis intersect is called ……………

Ans. Origin

(16) What is abscissa and ordinate of point (-4, -3) ?

(A) x = -4, y = -3

(B) x = -3, y = -4

(C) x = 4, y = 3

(D) None

Ans. (A)  x = -4, y = -3

(17) On joining the points (0, 0), (0, 2), (2, 2) and (2, 0) we obtain a :

(A) Square

(B) Rectangle

(C) Rhombus

(D) Parallelogram

Ans. (A) Square

(18) The sum of any two sides of a triangle is …………… than the third side.

Ans. Greater

(19) The diagonals of a rectangle are …………..

Ans. Equal

(20) If diagonals of quadrilateral bisect each other at right angles, then it is a :

(A) Parallelogram

(B) Rectangle

(C) Rhombus

(D) Trapezium

Ans. (C) Rhombus

(21) Angles in the  same segment of a circle are ……………

Ans. Equal

(22) In cyclic quadrilateral ABCD, AOC is the diameter of circle. If ∠CAD = 50°, then ∠ACD is :

Ans.

∠D = 90° ( because AC = diameter and all angles in semi circle are 90°)

∠ACD = 180° – (90°+50°) = 180° – 140° = 40°

(23) The centre of a circle lies in …………… of the circle :

(A) exterior

(B) circumference

(C) interior

(D) perimeter

Ans. (C) interior

(24) In a pair of set, a triangle is with angles :

(A) 30°, 60°, 90°

(B) 30°, 30°, 45°

(C) 75°, 25°, 80°

(D) 65°, 15°, 100°

Ans. (A) 30°, 60°, 90°

(25) To construct a triangle we must know at least its …………. parts.

Ans. Three

(26) To construct an angle of 22½° which angle we bisect ?

Ans. 22½° × 2 = 45°

(27) Perimeter of an isosceles triangle is 30 cm and its equal sides are of 12 cm, then area of the triangle is :

(A) 8√15 cm²

(B) 7√12 cm²

(C) 9√15 cm²

(D) 15√15 cm²

Ans. (C) 9√15 cm²

Perimeter= 30 cm

Semi Perimeter, s = 30/2 = 15 cm

a = b = 12 cm

c = 30 – (12+12) = 30 – 24 = 6 cm

Using Heron’s Formula,

Area = √s(s-a)(s-b)(s-c) = √15(15-12)(15-12)(15-6) = √15(3)(3)(9) = 9√15 cm²

(28) Base of a triangle is 12 cm and its height is 8 cm, then what will be its area ?

Ans. Area = ½ × base × height = ½ × 12 × 8 = 48 cm²

(29) Area of equilateral triangle with side a is ………….

Ans. (√3/4)a²

(30) The surface area of a cuboid is ………….

Ans. S.A or T.S.A = 2(lb + bh + bl)

(31) Volume of a hemisphere with radius r will be …………..

Ans. Volume of a hemisphere = ⅔πr³

Q32. Find the volume of right circular cone with radius 6 cm and height 7 cm.

Ans. Volume = ⅓πr²h = ⅓ × 22/7 × 6 × 6 × 7 = 264 cm³

(33) What will be the total surface area of a cylinder, when radius r and height h is given ?

(A) 2πrh

(B) 2πr(r+h)

(C) πr²h

(D) 2πr²

Ans. (B) 2πr(r+h) = 2πr² + 2πrh

(34) A cuboidal vessel is 10 m long and 8 m wide. How high must it be made to hold 380 cubic meters of a liquid ?

(A) 4.50 m

(B) 3.75 m

(C) 4.75 m

(D) 3.50 m

Ans. (C) 4.75 m

Volume = length × breadth × height

V = lbh

h = V ÷ lb = 380 ÷ (10×8) = 380 ÷ 80 = 4.75 m

(35) The mean of all possible factors of 20 will be ………….

Sol.

Factors of 20 are = 1, 2, 4, 5, 10, 20

Mean = (1+2+4+5+10+20)/6 = 42/6 = 7

(36) Class mark of class 150–160 is :

(A) 145

(B) 310

(C) 10

(D) 155

Ans. (D) 155

Class Mark = Mid Value = (150+160)/2 = 310/2 = 155

(37) The heights of 9 students of a class are given (in cm) as follows :

155, 160, 145, 149, 150, 147, 152, 144, 148

The median of this data is :

(A) 150

(B) 147

(C) 149

(D) 148

Ans. (C) 149

Ascending Order  144, 145, 147, 148, 149, 150, 152, 155, 160

Median = (n+1)/2 = (9+1)/2 = 10/2 = 5th Term = 149

(38) In a cricket match a lady batsman hits a boundary 6 times out of 30 balls she plays. The probability that she will not hit a boundary in the next ball is …………..

Ans.  24/30 = 4/5

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