Which angle is less than 90 degrees?

Which angle is less than 90 degrees?

• A. Acute angle
• B. Straight angle
• C. Right angle
• D. Obtuse angle

Answer: (A)

Angle measures are categorized by size: an acute angle is any angle smaller than a right angle, meaning less than 90 degrees. A right angle is exactly 90 degrees, an obtuse angle is greater than 90 but less than 180, and a straight angle is 180 degrees. Therefore, because the question asks for an angle less than 90 degrees, the correct term is acute angle.

Angle measures are categorized by size: an acute angle is any angle smaller than a right angle, meaning less than 90 degrees. A right angle is exactly 90 degrees, an obtuse angle is greater than 90 but less than 180, and a straight angle is 180 degrees. Therefore, because the question asks for an angle less than 90 degrees, the correct term is acute angle.