A reflex angle is an angle measuring more than 180 degrees and less than 360 degrees.

A triangle is a polygon with three angles whose sum is equal to 180 degrees.

This means that the sum of the three angles must equal 180 degrees. If one of those angles is more than 180 degrees, there is no room for two more angles. (They would have to be negative in measure, not possible.)

Therefore all angles in a triangle must measure less than 180 degrees and more than 0 degrees.

In a triangle the sum of all the three angles has to be equal to 180 degrees. This implies that every angle is less than 180 degrees. Even an angle of 180 degrees is not possible in a triangle.

A reflex angle is defined as one that is greater than 180 degrees and less than 360 degrees. If there were a reflux angle in a triangle the sum of the other two angles would have to be a negative number, which is not possible. Therefore it is not possible to have a reflux angle in a triangle.

A triangle cannot have reflex angles.

Explanation:

A reflex angle is an angle whose measure is more than 180 degree and less than 360 degree.

A triangle is a convex bounded shape by 3 straight lines, with 3 vertices and 3 angles at the 3 vertices.

The sum of all the three (internal ) angles of a triangle is 180 degree.

Therefore, every the angles in a triangle is more than zero less than 180 degree .

Therefore no internal angle of a triangle bounded by 3 sraight edges could be more than 180 degree.