sum of the interior angles of a triangle #2 is 180 °.
sum of the interior angles of a triangle #2 is 180 °.
sum of the interior angles of a triangle #2?
180 °
sum of angles of a triangle









































in several geometries, a triangle has three "vertices" and three "sides", where three angles of a triangle are formed at each vertex by a pair of adjacent sides. in a euclidean space, the sum of measures of these three angles of any triangle is invariably equal to the straight angle, also expressed as 180 °,  radians, two right angles, or a half-turn.
sum of angles of a triangle
the sum of the measures of the interior angles of a triangle in euclidean space is always 180 degrees. this fact is equivalent to euclid's parallel postulate. this allows determination of the measure of the third angle of any triangle given the measure of two angles. an "exterior angle" of a triangle is an angle that is a linear pair (and hence supplementary) to an interior angle. the measure of an exterior angle of a triangle is equal to the sum of the measures of the two interior angles that are not adjacent to it; this is the exterior angle theorem. the sum of the measures of the three exterior angles (one for each vertex) of any triangle is 360 degrees.
triangle