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COMEDK · Maths · 27. Application of Derivatives

A circular sector of perimeter \(60 \mathrm{~m}\) with maximum area is to be constructed, The radius of the circular arc in metre must be

  1. A 10
  2. B 15
  3. C 5
  4. D 20
Verified Solution

Answer & Solution

Correct Answer

(B) 15

Step-by-step Solution

Detailed explanation

Perimeter of sector \(=2 r+r \theta\) \(\Rightarrow \quad 60=2 r+r \theta\) (given) \(\Rightarrow \quad \theta=\frac{60-2 r}{r}\) Now, area of sector, \((A)=\frac{\pi r^{2} \theta}{360^{\circ}}=\frac{\pi r^{2}(60-2 r)}{360 r}\)…