Question

how many acute angles are in triangle def? number of acute angles:

Explanation:

Step1: Recall the definition of acute angle

An acute angle is an angle whose measure is less than \(90^{\circ}\).

Step2: Analyze the angles in triangle \(DEF\)

In any triangle, the sum of interior angles is \(180^{\circ}\). From the shape of triangle \(DEF\) (it is an obtuse - angled triangle, assume the obtuse angle is at \(E\)), since one angle (\(\angle E\)) is greater than \(90^{\circ}\), the sum of the other two angles (\(\angle D\) and \(\angle F\)) is less than \(90^{\circ}\). So \(\angle D\) and \(\angle F\) are acute angles.

Answer:

2