Question

Which of the following best describes the given triangle.

• A. Equilateral obtuse triangle
• B. Isosceles right triangle
• C. Isosceles obtuse triangle
• D. Isosceles acute triangle.

Answer 1

Answer: (C)

Isosceles obtuse triangle

Let the third angle be $x$

It is known that sum of interior angles of a triangle is ${180}^o$

Thus, $x+{36}^{\circ }+{36}^{\circ }={180}^{\circ }$

$\Rightarrow x={108}^{\circ }$

Now two of angles of the triangle are equal and one angle is greater than ${90}^{\circ }$

So the given triangle is an isosceles obtuse triangle.