Question

If one angle of a triangle is equal to the sum of the other two angles, then the triangle is an isosceles triangle.

• A. An isosceles triangle
• B. An obtuse triangle

Answer 1

The correct option is B

An obtuse triangle

The sum of all the angles of a triangle=180${}^{\circ }$

Let us assume the three angles of the triangle be x, y, and z such that x=y+z (as per the question)

So $x+y+z$ =180${}^{\circ }$

Substituting the value of y+z as x in the above equation we get:

$\Rightarrow$ $x+x$ =180${}^{\circ }$

$\Rightarrow$ $2x$ =180${}^{\circ }$

$\Rightarrow$ $x$ =90${}^{\circ }$

Therefore one of the angles of the above triangle is 90^o so the triangle is a right triangle.