Question

If one angle of a triangle is equal to the sum of the other two angles, the triangle is 

(a) obtuse (b) acute (c) right (d) equilateral

Answer 1

(c) right

Let angles of a triangle be x, y, z

such that x = y + z ………. (i)

Now, x + y + z = 180° [Angle sum property]

⇒ x + x = 180° [Using (1)]

⇒ 2x = 180°

⇒ x = 180°/2 = 90°

Thus, triangle is right angled.