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If D, G and R denote respectively the number of degrees, grades and radians in an angle, the

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Question

If D, G and R denote respectively the number of degrees, grades and radians in an angle, the 

Options

  • \[\frac{D}{90} = \frac{G}{100} = \frac{R}{\pi}\]

  • \[\frac{D}{90} = \frac{G}{100} = \frac{R}{\pi}\]

  • \[\frac{D}{90} = \frac{G}{100} = \frac{2R}{\pi}\]

  • \[\frac{D}{90} = \frac{G}{100} = \frac{R}{2\pi}\]
MCQ
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Solution

\[\frac{D}{90} = \frac{G}{100} = \frac{2R}{\pi}\]

Explanation:

Let θ be the angle which is measure in degree, radian and grade.

We know that 90° = 1 right angle

⇒ 1° = `1/90` right angle

⇒ D° = `"D"/90` right angle

⇒ `theta = "D"/90` right angle    ...(1)

Also we know that, π radians = 2 right angles

⇒ 1C = `2/pi` right angle

⇒ R = `2/pi xx` R right angle 

⇒ `theta = 2/pi xx` R right angle   ...(2)

Also we know that, 100 grades = 1 right angle 

⇒ 1 grade = `1/100` right angle

⇒ G grade = `"G"/100` right angle

⇒ `theta = "G"/100` right angles   ...(3)

From (1), (2) and (3)

∴ `"D"/90 = "2R"/pi = "G"/100`

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Chapter 4: Measurement of Angles - Exercise 4.2 [Page 17]

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R.D. Sharma Mathematics [English] Class 11
Chapter 4 Measurement of Angles
Exercise 4.2 | Q 1 | Page 17

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