What is the area of the triangle ABC with sides a = 10cm  and c = 4cm angle B = 30°?

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NDA (Held On: 18 Apr 2021) Maths Previous Year paper
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  1. 16 cm2
  2. 12 cm2
  3. 10 cm2
  4. 8 cm2

Answer (Detailed Solution Below)

Option 3 : 10 cm2
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NDA 01/2025: English Subject Test
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Detailed Solution

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Concept:

Area of a triangle =  × base × altitude

Area of ΔABC = 

 

Calculation:

Area of a triangle =  × base × altitude

 × c × a sin∠CBA

 × 10 cm × 4cm sin 30° 

= 5 × 4 ×  (as sin 30° = )

= 10 cm2

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