Question

In a triangle ABC, $\angle B=\angle C={45}^o$, then the triangle is ........................

• A. right angled triangle
• B. acute angled triangle
• C. obtuse angle triangle
• D. equilateral triangle

Answer 1

The correct option is A right angled triangle

In $△ABC$,

$\angle A+\angle B+\angle C={180}^o$ [Sum of all the interior angles of the triangle is ${180}^o$]

$\angle A+{45}^o+{45}^o={180}^o$ [$\angle B=\angle C={45}^o$ Given ]

$\Rightarrow \angle A={180}^o-{90}^o={90}^o$

As one angle of the triangle is ${90}^o$,

$\therefore$ It is right angled triangle.