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In ΔABC, AaBbCccosAa=cosBb cosCc. If a = 16, then the area of the triangle is ______. -

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Question

In ΔABC, `cos"A"/"a" = cos"B"/"b"  cos"C"/"c"`. If a = `1/sqrt(6)`, then the area of the triangle is ______.

Options

  • `1/8` sq. units

  • `1/(8sqrt(3)` sq. units

  • `1/24` sq. units

  • `1/(24sqrt(3)` sq. units

MCQ
Fill in the Blanks

Solution

In ΔABC, `cos"A"/"a" = cos"B"/"b"  cos"C"/"c"`. If a = `1/sqrt(6)`, then the area of the triangle is `1/(8sqrt(3)` sq. units.

Explanation:

Given, `cos"A"/"a" = cos"B"/"b"  cos"C"/"c"`

∴ `cos"A"/("k" sin "A")  = cos"B"/("k" sin "B")= cos"C"/("k" sin "C")`  .......[By sine rule]

⇒ cot A = cot B = cot C

∴ ΔABC is equilateral.

∴ Area of the equilateral triangle = `sqrt(3)/4` (side)2

= `sqrt(3)/4 (1/sqrt(6))^2`

= `sqrt(3)/24`

= `1/(8sqrt(3))` sq. unis

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