Trigonometric Equations Question 224

Question: In $ \Delta ABC, $ $ a^{2}+b^{2}+c^{2}=ac+ab\sqrt{3}, $ then triangle is

[MP PET 2004]

Options:

A) Equilateral

B) Isosceles

C) Right angled

D) None of these

Show Answer

Answer:

Correct Answer: C

Solution:

  • We have, $ a^{2}+b^{2}+c^{2}-ac-ab\sqrt{3}=0 $ $ \frac{a^{2}}{4}-,ac+c^{2}+\frac{3a^{2}}{4}+b^{2}-ab\sqrt{3}=0 $ $ {{[ \frac{a}{2}-c ]}^{2}}+{{[ \frac{\sqrt{3}a}{2}-b ]}^{2}}=0 $ i.e, $ a=2c $ and $ 2b=\sqrt{3}a $ i.e., $ b^{2}+c^{2}=a^{2} $ Hence triangle is right angled.