JEE Mains · Maths · STD 11 - Trigonometrical equations
The angles \(A, B\) and \(C\) of a triangle \(ABC\) are in \(A.P\) and \(a : b = 1 : \sqrt 3 .\) If \(c = 4\, cm,\) then the area (in sq. cm) of this triangle is
- A \(2\sqrt 3\)
- B \(\frac{4}{{\sqrt 3 }}\)
- C \(4\sqrt 3\)
- D \(\frac{2}{{\sqrt 3 }}\)
Answer & Solution
Correct Answer
(A) \(2\sqrt 3\)
Step-by-step Solution
Detailed explanation
\(\angle B\, = \,\frac{\pi }{3},\) by sine Rule \(\sin \,A\, = \frac{1}{2}\) \( \Rightarrow \,A\, = \,{30^o},\,a\, = \,2\,,\,b\, = \,2\sqrt 3 \,,\,c\, = \,4\) \(\Delta = \frac{1}{2} \times 2\sqrt 3 \times 2\, = \,2\sqrt 3 \,sq.\,cm\)
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