In a triangle ABC, ∠A = 75° and ∠B = 45°. What is 2a - b equal to?

This question was previously asked in
NDA-II 2024 (Maths) Official Paper (Held On: 01 Sept, 2024)
View all NDA Papers >
  1. c
  2. √2c
  3. 2c
  4. 2√2c

Answer (Detailed Solution Below)

Option 2 : √2c
Free
NDA 01/2025: English Subject Test
30 Qs. 120 Marks 30 Mins

Detailed Solution

Download Solution PDF
Concept:

Triangle Angle Sum Property:

  • In a triangle, the sum of all interior angles is always equal to 180º.
  • Given angles can be used to find the unknown angle using the formula:
  • Once all angles are known, trigonometric ratios can be used to relate the sides of the triangle.
  • Law of Sines:
  • The Law of Sines states that in any triangle, the ratio of the length of a side to the sine of its opposite angle is constant:
  • Here, a, b, and c are the sides opposite to angles A, B, and C respectively.

 

Calculation:

Given,

Angle A = 75º

Angle B = 45º

Using the triangle angle sum property, find angle C:

⇒ ∠C = 180º - (∠A + ∠B)

⇒ ∠C = 180º - (75º + 45º)

⇒ ∠C = 180º - 120º

⇒ ∠C = 60º

Now, using the Law of Sines:

⇒ 

⇒ 

Now

⇒  2a - b = 

∴ Option (b) is correct.

Latest NDA Updates

Last updated on May 30, 2025

->UPSC has released UPSC NDA 2 Notification on 28th May 2025 announcing the NDA 2 vacancies.

-> A total of 406 vacancies have been announced for NDA 2 Exam 2025.

->The NDA exam date 2025 has been announced for cycle 2. The written examination will be held on 14th September 2025.

-> Earlier, the UPSC NDA 1 Exam Result has been released on the official website.

-> The selection process for the NDA exam includes a Written Exam and SSB Interview.

-> Candidates who get successful selection under UPSC NDA will get a salary range between Rs. 15,600 to Rs. 39,100. 

-> Candidates must go through the NDA previous year question paper. Attempting the NDA mock test is also essential. 

Hot Links: rummy teen patti teen patti bindaas teen patti real cash withdrawal teen patti joy vip teen patti chart