Question

how many obtuse angles are in an obtuse triangle? 0 2 1 3

Explanation:

Step1: Recall triangle angle sum

The sum of angles in a triangle is $180^\circ$.

Step2: Define obtuse angle

An obtuse angle is $>90^\circ$.

Step3: Test multiple obtuse angles

If there were 2 obtuse angles, their sum would be $>180^\circ$, violating the angle sum rule.

Step4: Confirm obtuse triangle definition

An obtuse triangle has exactly one obtuse angle, with the other two angles acute (sum to $<90^\circ$).

Answer:

1