List down the properties of a triangle that you have learned before.
[list=1][*]Sides & Vertices: A triangle has three straight sides and three vertices.[/*][*]Angle Sum: The sum of interior angles is 180°. The sum of exterior angles is 360°.[/*][*]Triangle Inequality: The sum of the lengths of any two sides must be greater than the length of the third side.[/*][*]Side-Angle Relationship: The longest side is always opposite the largest angle, and the shortest side is opposite the smallest angle.[br][/*][*]Equilateral triangle: All three sides are equal, and all three angles are 60° each.[/*][*]Isosceles triangle: Two sides and the two angles opposite those sides are equal.[/*][*]Scalene triangle: All sides and all angles are different.[/*][*]Right-angled triangle: Has one 90° angle, satisfies the Pythagoras theorem [math]\left(a^2+b^{^2}=c^2\right)[/math]. [br][/*][/list]