To determine which of the given angles is an acute angle, it’s important to know the definition of an acute angle. An acute angle is an angle that is less than 90 degrees.
Here are the three angles provided in the question:
- 86°
- 90°
- 126°
Let's evaluate each angle:
1. 86°: This angle is less than 90 degrees, so it is an acute angle.
2. 90°: This angle is exactly 90 degrees, which makes it a right angle, not an acute angle.
3. 126°: This angle is greater than 90 degrees, so it is an obtuse angle, not an acute angle.
Based on this evaluation, the only angle that is an acute angle is 86°. Thus, the measure of an acute angle among the given options is:
○ A. 86°
