The measure of all angles of the triangle is given to be 60 degrees. This invariably means we are talking about an equilateral triangle as all angles of an equilateral triangle are equal.
Also all sides of an equilateral triangle is known to be equal. Therefore the measure of all sides of the concerned triangle are equal.
Given the measure of two length of sides are 6 cm respectively.
Therefore the length of side 3 is 6 cm, equal to the other two sides.
