Maths · Trigonometrical identities and trigonometrical functions

If one angle of a triangle equals the sum of the other two angles, the triangle

If one angle of a triangle equals the sum of the other two angles, the triangle must be:

  • A. scalene
  • B. right angled
  • C. obtuse angled
  • D. acute angled

Step-by-step solution

Let the three angles be x, y, z. Given x = y + z. Since sum of angles = 180°, x + y + z = 180°. Substituting, (y+z) + y + z = 2(y+z) = 180°, so y+z = 90°, hence x = 90°. Therefore the triangle is right-angled.
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