Right Angle Verification: Determining 90-Degree Angles in Geometry

To solve this problem, we need to recall the definition of a right angle.

A right angle is defined as an angle that measures exactly $90^\circ$. This is a standard definition found in geometry, describing an angle formed by the intersection of two perpendicular lines.

Given the multiple-choice options, we need to identify which one corresponds to a right angle:

• A right angle measures $90^\circ$.

Let's examine the provided choices:

1. Angle of 180°.
2. Minor angle of 90°.
3. Angle of 90°.
4. Angle greater than 90°.

Choice 3, "Angle of 90°," directly matches the definition of a right angle.

Therefore, the correct answer is Angle of 90°.