FORMS - Triangle

The angles of any triangle, regardless of type, always add up to 180°. The sum of the lengths of any two sides of a triangle is greater than the length of the third side, and the difference between the lengths of two sides is less than the length of the third side. In a triangle, the side opposite the largest angle is the longest. The exterior angle of a triangle is equal to the sum of its two interior opposite angles, a relationship known as the exterior angle property. Two triangles are considered similar if their corresponding angles are congruent and their sides are proportional in length. The area of a triangle is calculated using the formula ½ × base × height, and its perimeter is the sum of the lengths of all three sides.