Angle Classification Quiz

What type of angle is exactly 90 degrees?

• Acute

• Right

• Obtuse

• Straight

Answer explanation

A right angle is defined as an angle that measures exactly 90 degrees. Acute angles are less than 90 degrees, obtuse angles are greater than 90 degrees but less than 180 degrees, and straight angles measure 180 degrees.

An angle that measures 45 degrees is classified as which type of angle?

• Right

• Straight

• Acute

• Obtuse

Answer explanation

An angle measuring 45 degrees is less than 90 degrees, which classifies it as an acute angle. Right angles are exactly 90 degrees, straight angles are 180 degrees, and obtuse angles are greater than 90 degrees.

Which of the following angles is greater than 90 degrees but less than 180 degrees?

• Right

• Straight

• Acute

• Obtuse

Answer explanation

An obtuse angle is defined as one that is greater than 90 degrees but less than 180 degrees. Therefore, the correct choice is 'Obtuse', while the other options (Right, Straight, Acute) do not fit this definition.

An angle that measures 180 degrees is known as a:

• Right angle

• Straight angle

• Acute angle

• Obtuse angle

Answer explanation

An angle that measures 180 degrees is called a straight angle. It forms a straight line, distinguishing it from right angles (90 degrees), acute angles (less than 90 degrees), and obtuse angles (greater than 90 degrees).

Which angle is smaller than a right angle?

• Straight

• Obtuse

• Acute

• Reflex

Answer explanation

An acute angle is defined as an angle that is less than 90 degrees, making it smaller than a right angle. In contrast, straight angles are 180 degrees, obtuse angles are between 90 and 180 degrees, and reflex angles are greater than 180 degrees.

If an angle measures 120 degrees, it is classified as:

• Acute

• Right

• Obtuse

• Straight

Answer explanation

An angle measuring 120 degrees is greater than 90 degrees but less than 180 degrees, which classifies it as obtuse. Acute angles are less than 90 degrees, right angles are exactly 90 degrees, and straight angles are 180 degrees.

What is the classification of an angle that measures 0 degrees?

• Right

• Acute

• Zero

• Straight

Answer explanation

An angle measuring 0 degrees is classified as a zero angle. It is the smallest angle possible, while right angles measure 90 degrees, acute angles are less than 90 degrees, and straight angles measure 180 degrees.

An angle that is exactly 180 degrees is called a:

• Right angle

• Straight angle

• Acute angle

• Obtuse angle

Answer explanation

An angle that measures exactly 180 degrees is called a straight angle. It forms a straight line, distinguishing it from right angles (90 degrees), acute angles (less than 90 degrees), and obtuse angles (greater than 90 but less than 180 degrees).

Which of the following angles is less than 90 degrees?

• Right

• Straight

• Acute

• Obtuse

Answer explanation

An acute angle is defined as an angle that is less than 90 degrees. In contrast, a right angle is exactly 90 degrees, a straight angle is 180 degrees, and an obtuse angle is greater than 90 degrees.

An angle that measures 90 degrees is known as a:

• Right angle

• Straight angle

• Acute angle

• Obtuse angle

Answer explanation

An angle that measures exactly 90 degrees is called a right angle. This is distinct from other types of angles: straight angles measure 180 degrees, acute angles are less than 90 degrees, and obtuse angles are greater than 90 degrees.