Plane angle

Definition of plane angle:

The plane angle is the one that measures $180°$ .

Which of the 4 angles shown in the figure corresponds to the description of the plane angle?

The correct answer is C) 180 °

Detailed explanation

Start practice

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

True or false?

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

Practice more now

If you are interested in learning more about other angle topics, you can enter one of the following articles:

On the website of Tutorela you will find a variety of articles on mathematics.

Examples and exercises with solutions of plane angle

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 statement is true.

Answer

True

Exercise #3

If two adjacent angles are not equal to one another, then one of them is obtuse and the other is 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) and (c), we can observe that the angle symbol is a symbol representing an angle that equals 90 degrees.

Answer

Exercise #5

Which of the following angles are obtuse?

Video Solution

Step-by-Step Solution

By definition, an obtuse angle is an angle that is greater than 90 degrees. We can observe that in one drawing there is an angle of 90 degrees and therefore it is not an obtuse angle, the other two angles are less than 90 degrees meaning they are also not obtuse, they are acute angles.

Therefore, none of the answers is correct.