2014 · Q84
If for a triangle the radius of the circumcircle is double the radius of the inscribed circle, then which one of the following is correct?
Elementary MathematicsCircles
- AThe triangle is right angled
- BThe triangle is isosceles
- CThe triangle is equilateral
- DNone of the above
Explanation
Euler's inequality R ≥ 2r holds with equality only for the equilateral triangle.