Question

please ans ques 6,7

Answer 1

6. Let the angles be A,B and C.
    According to question, A = B + C .
 
Sum of all angles of a triangle = 180°
⇒ A + B + C = 180°
⇒ 2A = 180°
⇒ A = 90°

So, here we get an angle of the given triangle that is 90°, therefore it is a right angled triangle.

7.    (For sake of writing here, I am writing the angles simply as A,B and C)
      3A = 4B = 6C

     Sum of angles of a triangle = 180°
⇒ A +B +C = 180°
⇒ 2C + 3C/2 + C = 180°
⇒9C/2 = 180°
⇒C = 40°

A = 80°, B = 60°, C = 40°