Back to Student Worksheet
Math Grade 2-3 Answer Key

Types of Angles: Right, Acute, and Obtuse

Identify angles by comparing them to a square corner

Answer Key
Name:
Date:
Score: / 15

Types of Angles: Right, Acute, and Obtuse

Identify angles by comparing them to a square corner

Math - Grade 2-3

Instructions: Read each problem carefully. Decide whether each angle is right, acute, or obtuse. Show your thinking in the space provided.
  1. 1

    An angle makes a perfect square corner, like the corner of a book. What type of angle is it?

    A right angle looks like the corner of a piece of paper.

    It is a right angle because it makes a perfect square corner.
  2. 2

    An angle is smaller than a right angle. What type of angle is it?

    It is an acute angle because it is smaller than a right angle.
  3. 3

    An angle is wider than a right angle but not a straight line. What type of angle is it?

    Think of an angle that opens wider than the corner of a book.

    It is an obtuse angle because it is wider than a right angle but not a straight line.
  4. 4

    Look at the angle shown. It opens only a little bit. Is it right, acute, or obtuse?

    The angle is acute because it opens less than a right angle.
  5. 5

    Look at the angle shown. It opens wide, more than a square corner. Is it right, acute, or obtuse?

    Compare the opening to the corner of a square.

    The angle is obtuse because it opens wider than a right angle.
  6. 6

    A door is opened just a little. The angle between the door and the wall is small. What type of angle is this?

    The angle is acute because the opening is smaller than a right angle.
  7. 7

    A notebook page has four corners. What type of angle is each corner?

    Most paper corners are square corners.

    Each corner is a right angle because each corner makes a square corner.
  8. 8

    Look at the clock. The minute hand points to 12 and the hour hand points to 3. What type of angle do the hands make?

    The clock hands make a right angle because they form a square corner.
  9. 9

    Look at the clock. The minute hand points to 12 and the hour hand points to 2. What type of angle do the hands make?

    The hand at 2 is closer to 12 than the hand at 3.

    The clock hands make an acute angle because the angle is smaller than a right angle.
  10. 10

    Look at the clock. The minute hand points to 12 and the hour hand points to 5. What type of angle do the hands make?

    The clock hands make an obtuse angle because the angle is wider than a right angle.
  11. 11

    Draw one acute angle. Then write one sentence explaining why it is acute.

    Make the two sides of the angle close together.

    The drawing should show an angle smaller than a right angle. It is acute because it opens less than a square corner.
  12. 12

    Draw one right angle. Then write one sentence explaining why it is right.

    The drawing should show a square corner. It is a right angle because it matches the corner of a square or paper.
  13. 13

    Draw one obtuse angle. Then write one sentence explaining why it is obtuse.

    Open the angle wider than an L shape, but do not make it a straight line.

    The drawing should show an angle wider than a right angle. It is obtuse because it opens more than a square corner.
  14. 14

    A triangle has one angle that is larger than a square corner. What type of angle is that angle?

    That angle is an obtuse angle because it is larger than a right angle.
  15. 15

    Sort these angles into three groups: right angle, acute angle, and obtuse angle. Angle A is a square corner. Angle B is smaller than a square corner. Angle C is wider than a square corner.

    Compare each angle to a square corner.

    Angle A is a right angle. Angle B is an acute angle. Angle C is an obtuse angle.
LivePhysics™.com Math - Grade 2-3 - Answer Key