Which statement is true about an angle with a measure of 180 degrees?

Which statement is true about an angle with a measure of 180 degrees?

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

Answer: (D)

Angles are classified by their measures. An angle that measures 180 degrees forms a straight line, with the two rays pointing in opposite directions from a common endpoint. That is a straight angle. Acute angles are less than 90 degrees, so they look like small openings. A right angle is exactly 90 degrees, like a perfect corner. An obtuse angle is greater than 90 degrees but less than 180, opening wider than a right angle but not all the way straight. Since 180 degrees sits exactly on the straight line, it fits the straight angle description rather than acute, right, or obtuse.

Angles are classified by their measures. An angle that measures 180 degrees forms a straight line, with the two rays pointing in opposite directions from a common endpoint. That is a straight angle.

Acute angles are less than 90 degrees, so they look like small openings. A right angle is exactly 90 degrees, like a perfect corner. An obtuse angle is greater than 90 degrees but less than 180, opening wider than a right angle but not all the way straight. Since 180 degrees sits exactly on the straight line, it fits the straight angle description rather than acute, right, or obtuse.