A triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry.

1. Scalene: All sides are of different lengths. 2. Isosceles: Two sides are of equal length. 3. Equilateral: All three sides are of equal length.

1. Acute: All angles are less than 90 degrees. 2. Right: One angle is exactly 90 degrees. 3. Obtuse: One angle is greater than 90 degrees.

It is classified as an Isosceles Acute triangle.

It is classified as a Scalene Right triangle.

The sum of the interior angles of a triangle is always 180 degrees.

The other two angles must be acute and their sum must equal 90 degrees.

The missing angle can be found using the formula: Missing Angle = 180 - (Angle1 + Angle2).

The third angle measures 50 degrees.

An exterior angle is formed by one side of the triangle and the extension of an adjacent side. It is equal to the sum of the two opposite interior angles.