Acute Angles

🏆Practice types of aangles (right, acute, obtuse, flat)

Definition of an acute angle

An acute angle is an angle that measures less than 90° 90° .

Acute angles can appear in triangles, parallelograms, and other geometric shapes where there is an angle less than 90° 90° degrees.

Acute angle

A1- acute angle

Which of the 4 angles presented in the figure corresponds to the description of the acute angle?

what is the definitions of 4 angles

The correct answer is B) 40°

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Test yourself on types of aangles (right, acute, obtuse, flat)!

einstein

True or false?

One of the angles in a rectangle may be an acute angle.

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If you are interested in learning more about other topics related to angles, you can check out one of the following articles:

  • Angle Notation
  • Sides, Vertices, and Angles
  • Bisector
  • Right Angle
  • Obtuse Angle
  • Straight Angle
  • Adjacent Angles
  • Vertically Opposite Angles
  • Alternate Angles
  • Corresponding Angles
  • Sum of the Angles of a Triangle
  • Sum of the Angles of a Polygon
  • Sum and Difference of Angles

On the Tutorela website, you will find a wide variety of articles about mathematics

Examples and exercises with solutions of acute angles

Exercise #1

True or false?

One of the angles in a rectangle may be an acute angle.

Video Solution

Step-by-Step Solution

One of the properties of a rectangle is that all its angles are right angles.

Therefore, it is not possible for an angle to be acute, that is, less than 90 degrees.

Answer

False

Exercise #2

True or false?

An acute angle is smaller than a right angle.

Step-by-Step Solution

The definition of an acute angle is an angle that is smaller than 90 degrees.

Since an angle that equals 90 degrees is a right angle, the answer is correct.

Answer

True

Exercise #3

If the two adjacent angles are not equal to each other, then one of them is obtuse and the other acute.

Video Solution

Step-by-Step Solution

The answer is correct because the sum of two acute angles will be less than 180 degrees and the sum of two obtuse angles will be greater than 180 degrees

Answer

True

Exercise #4

Which figure depicts a right angle?

Video Solution

Step-by-Step Solution

A right angle is equal to 90 degrees. In diagrams A+C, we see that the angle symbol is a symbol representing an angle that equals 90 degrees.

Answer

Exercise #5

Choose the appropriate triangle according to the following:

Angle B equals 90 degrees.

Video Solution

Step-by-Step Solution

Let's note in which of the triangles angle B forms a right angle, meaning an angle of 90 degrees.

In answers C+D, we can see that angle B is smaller than 90 degrees.

In answer A, it is equal to 90 degrees.

Answer

AAABBBCCC

Review Questions

What is an angle?

An angle is the opening that occurs between two lines that join from a vertex. Angles can be measured in degrees or radians.


What is the classification of angles according to their measure?

Angles are classified into 6 types according to their measure:

  • Acute angle
  • Right angle
  • Obtuse angle
  • Straight angle
  • Reflex angle
  • Perigon angle or also called complete angle

What is an acute angle?

The acute angle is the narrowest angle of all according to its measure. In this case, an acute angle is one that measures less than 90o 90^o


Which of the following angles has a measure less than 90o 90^o degrees?

A) Angle of 200o 200^o

B) Angle of 160o 160^o

C) Angle of 30o 30^o

Answer: In this case, option C is the angle that corresponds to an angle less than 90o 90^o , that is, it is an acute angle.


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