41)If the ratio of radii of two spheres is 2 : 3, then the ratio of their surface areas is
A) 3 : 2
B) 4 : 9
C) 9 : 4
D) 8 : 27
1 : r2 = 2:31 : LSA2 1 2 : 4 πr2 2 2 :32
42)Ratio of volumes of a Cone, a Cylinder and a Hemi-sphere of same base radius and equal heights is ……………..
A) 1 : 2 : 3
B) 3 : 2 : 1
C) 1 : 3 : 2
D) 3 : 1 : 2
C) 1 : 3 : 2
Explanation:Required ratio of volumes of a cone, cylinder and a hemi-sphere
=
πr
2 h : πr
2 h :
πr
2 h
=1/3 :1/1:2/3
= 1:3:2
43)The area of equilateral triangle is 36 √3 cm2 , then the perimeter is…………………. cm
C) 36
Explanation:Area of equilateral △
le = 36√3
⇒ a
2 = 4 x 36
⇒a =
=2 x 6 = 12 cm
Perimeter of equilateral triangle
= 3 x side = 3 x 12 = 36 cm
44)If 3 tan A = 4 then sin A =
A) 3/4
B) 4/3
C) 4/5
D) 3/5
2 = 42 + 32
45)
A) 1/√3
B) √3
C) 1/2
D) 3
B) √3
Explanation:
= tan2θ = tan.2.30°
= tan 60° = √3
46)tan 48° . tan 42° =
47)(1 -cosθ) (1 + cosθ) =
A) sin2 θ
B) cos2 θ
C) tan2 θ
D) cot2 θ
2 θ2 θ = sin2 θ
48)If tanθ -cotθ = 1 then tan2 θ + cot2 θ =
2 + b2 = (a -b) 2 + 2ab tan2 θ + cot2 θ2 + 2 tanθ . 1/tanθ
49)If x = a cosθ, y = b secθ ⇒
A) xy = a2 b2
B) x2 y2 = ab
C) x2 y2 = a2 b2
D) None
2 y2 = a2 b2 2 θ . sec2 θ =12 (y/b)2 = 12 y2 = a2 b2
50)Length of shadow of a 12 m high pole is 4√3 metres in the morning. What is the angle of elevation of the sun rays with the ground at that time?
A) 30°
B) 45°
C) 15°
D) 60°
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πr2h : πr2h : 
πr2h
= 36√3
=2 x 6 = 12 cm
=