Two posts are x metres apart and the height of one is double tha

Subject

Quantitative Aptitude

Class

SSCCGL Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

81.
The area of the square inscribed in a circle of radius 8 cm is
  • 256 sq. cm.

  • 250 sq. cm.

  • 128 sq. cm.

  • 128 sq. cm.

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82.

X and Y are centres of circles of radii 9cm and 2 cm respectively, XY = 17cm. Z is the centre of a circle of radius r cm which touches the above circles externally. Given that angle XZY space equals space 90 degree comma the value of r is

  • 13 cm

  • 6 cm

  • 9 cm

  • 9 cm

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83.

I is the incentre of a triangle ABC. If angle ABC space equals space 65 degree and angle ACB space equals space 55 degree comma then the value of angle BIC is

  • 130°

  • 120°

  • 140°

  • 140°

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84.

If the radii of two circles be 6 cm and 3 cm and the length of the transverse common tangent be 8 cm, then the distance between the two centres is

  • square root of 145 space cm
  • square root of 140 space cm
  • square root of 150 space cm
  • square root of 150 space cm
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85.

The ratio between the number of sides of two regular polygons is 1 : 2 and the ratio between their interior angles is 2 : 3. The number of sides of these polygons is respectively.

  • 6, 12

  • 5, 10

  • 4, 8

  • 4, 8

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86.

Two posts are x metres apart and the height of one is double that of the other. If from the mid-point of the line joining their feet, an observer finds the angular elevations of their tops to be complementary, then the height (in metres) of the shorter post is

  • fraction numerator straight x over denominator 2 square root of 2 end fraction
  • straight x over 4
  • straight x square root of 2
  • straight x square root of 2


A.

fraction numerator straight x over denominator 2 square root of 2 end fraction

Let BD be the distance between two post i.e. x m (given)
therefore space OB space equals space OD space equals space straight x over 2 straight m
From ΔOCD,
  tan space straight theta space equals space fraction numerator straight h over denominator begin display style straight x over 2 end style end fraction space equals space fraction numerator 2 straight h over denominator straight x end fraction                 ...(i)

From ΔOAB,
tan left parenthesis 90 degree minus straight theta right parenthesis space equals space AB over BO
rightwards double arrow space space cot space straight theta space equals space fraction numerator 2 straight h over denominator begin display style straight x over 2 end style end fraction space equals space fraction numerator 4 straight h over denominator straight x end fraction space space          ...(ii)
Multiplying both equations,
tan space straight theta space. space cot space straight theta space equals space fraction numerator 2 straight h over denominator straight x end fraction space cross times space fraction numerator 4 straight h over denominator straight x end fraction
rightwards double arrow space space space space space straight x squared space equals space 8 straight h squared
rightwards double arrow space space space space straight h squared space equals space straight x squared over 8
rightwards double arrow space space space straight h space equals space fraction numerator straight x over denominator 2 square root of 2 end fraction space metre

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87.

If θ is a positive acute angle and tan 2θ tan 3θ = 1, then the value of 
left parenthesis 2 space cos squared straight theta fraction numerator 5 straight theta over denominator 2 end fraction minus 1 right parenthesis is

  • negative 1 half
  • 1

  • 0

  • 0

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88.

If sin space 17 degree space equals space straight x over straight y comma then the value of left parenthesis sec space 17 degree space minus space sin space 73 degree right parenthesis is

  • fraction numerator straight y squared over denominator straight x square root of straight y squared minus straight x squared end root end fraction
  • fraction numerator straight x squared over denominator straight y square root of straight y squared minus straight x squared end root end fraction
  • fraction numerator straight x squared over denominator straight y square root of straight x squared minus straight y squared end root end fraction
  • fraction numerator straight x squared over denominator straight y square root of straight x squared minus straight y squared end root end fraction
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89.

In a right-angled triangle, XYZ, right-angled at Y, If XY space equals space 2 square root of 6 and XZ - YZ = 2, then sec X + tan X is

  • fraction numerator 1 over denominator square root of 6 end fraction
  • square root of 6
  • 2 square root of 6
  • 2 square root of 6
311 Views

90.

If 0 degree space less than space straight theta space less than space 90 degree, the value of sin θ + cos θ is

  • equal to 1

  • greater than 1

  • less than 1

  • less than 1

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