Answer:
The sum of the angles within a triangle is 180 degree.
Explanation:
We are asked to determine why is it impossible for a triangle to contain a 180° angle.
We know that angle sum property of triangle states that sum of all three angles of triangle must be equal to 180°.
We also know that measure of angle on a straight line is 180 degrees. So, if an angle measure to 180 degrees, then it will be a line not a triangle.
Therefore, it is impossible for a triangle to contain a 180° angle.