Step 1: Understanding a Right Angle.
A right angle is an angle that measures exactly 90°. It is one of the basic types of angles in geometry and is formed when two lines meet at a perpendicular intersection.
Step 2: Verifying the Options.
- Option (1): A right angle measures 90°, making this the correct answer.
- Option (2): 45° is an acute angle, not a right angle.
- Option (3): 60° is an acute angle, not a right angle.
- Option (4): 120° is an obtuse angle, not a right angle.
Conclusion:
Therefore, the correct answer is (1) 90°.