Tick the property which justifies the answer to the following question:

SCORE :

If a triangle has two perpendicular sides, then it is a right triangle.
If a triangle has two complementary angles, then it is a right triangle.
If a triangle is right-angled, then the two acute angles are complementary.
If a triangle has three congruent sides, then it is an equilateral triangle.
If a triangle has all three congruent angles, then it is an equilateral triangle.
If a triangle has two 60 angles, then it is an equilateral triangle.
If a triangle is equilateral, then each angle is 60°.
If a triangle has two congruent sides, then it is an isosceles triangle.
If a triangle has two congruent angles, then it is an isosceles triangle.
If a triangle is isosceles, then it has two congruent angles.