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Abc is a Right Angled Triangle in Which ∠A = 90° and Ab = Ac. Find ∠B and ∠C.

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Question

ABC is a right angled triangle in which ∠A = 90° and AB = AC. Find ∠B and ∠C. 

 

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Solution

Given that ABC is a right angled triangle such that ∠A = 90° and AB = AC  Since,  

AB = AC ⇒ ΔABC is also isosceles 

∴ We can say that ΔABC is right angled isosceles triangle 

⇒ ∠C=∠B and ∠A=90°           ................(1) 

Now, we have
Sum of angled in a triangle =180°  

⇒ ∠A+∠B+∠C=180° 

⇒ 90°+∠B+∠B=180°            [∵ From (1)] 

⇒ 2∠B=180°-90° 

⇒`∠B=(90°)/2=45°`  

∴ ∠B=∠C=45°  

 

 

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Chapter 12: Congruent Triangles - Exercise 12.3 [Page 47]

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R.D. Sharma Mathematics [English] Class 9
Chapter 12 Congruent Triangles
Exercise 12.3 | Q 6 | Page 47

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