Triangle DEF contains two congruent acute angles. The sum of the measures of the two congruent acute angles is greater than 90 degrees. Anna concludes that the triangle must be an acute triangle. Which best describes her conclusion?
Anna's conclusion is incorrect. The statement "Triangle DEF contains two congruent acute angles" means that two angles in Triangle DEF are congruent and acute (less than 90 degrees). However, the fact that the sum of these two angles is greater than 90 degrees does not necessarily mean that the triangle is an acute triangle.
An acute triangle is a triangle in which all three angles are acute (less than 90 degrees). In this case, we only have information about two angles in the triangle. To determine whether the triangle is acute, we need to know the measure of the third angle as well. It's possible for Triangle DEF to be an obtuse triangle (with one angle greater than 90 degrees) or even a right triangle (with one angle exactly 90 degrees) in this scenario.
Therefore, Anna's conclusion that the triangle must be an acute triangle is not supported by the given information.