Examples with solutions for Angles in Parallel Lines: Generate a random angle

Exercise #1

Calculate the value of the angle X.

XXX4145

Video Solution

Step-by-Step Solution

To solve this problem, we will apply the triangle sum theorem:

  • Step 1: Identify the triangle formed by the known angles and the unknown angle X X .
  • Step 2: Use the triangle angle sum property which states: The sum of the angles in a triangle is 180 180^\circ .
  • Step 3: The known angles in the problem are 41 41^\circ and 45 45^\circ .

Now, let's complete the steps:

Step 1: The angles presented form a triangle involving the angles 41 41^\circ , 45 45^\circ , and X X .
Step 2: Apply the triangle angle sum theorem: 41+45+X=180 41^\circ + 45^\circ + X = 180^\circ .
Step 3: Simplifying this we get:

41+45+X=180 41 + 45 + X = 180

86+X=180 86 + X = 180

Solve for X X :

X=18086 X = 180 - 86

X=94 X = 94

Therefore, the value of angle X X is 94 94^\circ .

Answer

94

Exercise #2

What is the size of the missing angle?

80

Video Solution

Step-by-Step Solution

To find the size of the missing angle, we will use the property that the sum of angles on a straight line is 180180^\circ. Given that one angle is 8080^\circ, we can calculate the missing angle using the following steps:

  • Step 1: Recognize that the given angle α=80\alpha = 80^\circ and the missing angle β\beta form a straight line.
  • Step 2: Use the angle sum property for a straight line: α+β=180 \alpha + \beta = 180^\circ
  • Step 3: Substitute the known value: 80+β=180 80^\circ + \beta = 180^\circ
  • Step 4: Solve for the missing angle β\beta: β=18080=100 \beta = 180^\circ - 80^\circ = 100^\circ

Therefore, the size of the missing angle is 100100^\circ.

Answer

100°

Exercise #3

Calculate the expression

α+B \alpha+B B30150

Video Solution

Step-by-Step Solution

According to the definition of alternate angles:

Alternate angles are angles located on two different sides of the line that intersects two parallels, and that are also not on the same level with respect to the parallel to which they are adjacent.

It can be said that:

α=30 \alpha=30

β=150 \beta=150

And therefore:

30+150=180 30+150=180

Answer

180 180

Exercise #4

According to the drawing

What is the size of the angle? α \alpha ?

120

Video Solution

Step-by-Step Solution

Given that the angle
α \alpha is a corresponding angle to the angle 120 and is also equal to it, thereforeα=120 \alpha=120

Answer

120 120

Exercise #5

a is parallel to b.

Calculate the angles shown in the diagram.

115115115111222333444555666777aaabbb

Video Solution

Step-by-Step Solution

Given that according to the definition, the vertex angles are equal to each other, it can be argued that:

115=2 115=2 Now we can calculate the second pair of vertex angles in the same circle:

1=3 1=3

Since the sum of a plane angle is 180 degrees, angle 1 and angle 3 are complementary to 180 degrees and equal to 65 degrees.

We now notice that between the parallel lines there are corresponding and equal angles, and they are:

115=4 115=4

Since angle 4 is opposite to angle 6, it is equal to it and also equal to 65 degrees.

Another pair of alternate angles are angle 1 and angle 5.

We have proven that:1=3=65 1=3=65

Therefore, angle 5 is also equal to 65 degrees.

Since angle 7 is opposite to angle 5, it is equal to it and also equal to 115 degrees.

That is:

115=2=4=6 115=2=4=6

65=1=3=5=7 65=1=3=5=7

Answer

1, 3 , 5, 7 = 65°; 2, 4 , 6 = 115°

Exercise #6

Given two parallel lines

Calculate the angle α \alpha

α125

Video Solution

Step-by-Step Solution

The angle 125 and the angle alpha are vertically opposite angles, so they are equal to each other.

α=125 \alpha=125

Answer

125 125

Exercise #7

Calculates the size of the angle α \alpha

α40

Video Solution

Step-by-Step Solution

Let's review the definition of alternate angles between parallel lines:

Alternate angles are angles located on two different sides of the line that intersects two parallels, and that are also not at the same level with respect to the parallel they are adjacent to. Alternate angles have the same value as each other.

Therefore:

α=40 \alpha=40

Answer

40 40

Exercise #8

Angle 1 is 20 degrees.

Calculate the size of angle 2.

12

Video Solution

Step-by-Step Solution

Remember the definition of vertically opposite angles:

Vertically opposite angles are formed between two intersecting lines, and they actually have a common vertex and are opposite each other. Vertically opposite angles are equal in size.

Therefore:

1=2=20 1=2=20

Answer

20 20

Exercise #9

Look at the parallelogram in the diagram. Calculate the angles indicated.

3020βα

Video Solution

Step-by-Step Solution

a a is an alternate angle to the angle that equals 30 degrees. That meansα=30 \alpha=30 Now we can calculate: β \beta

As they are adjacent and theredore complementary angles to 180:

18030=150 180-30=150

Angleγ \gamma Is on one side with an angle of 20, which means:

γ=20 \gamma=20

Answer

α=30 \alpha=30 β=150 \beta=150 γ=20 \gamma=20

Exercise #10

Determine the value of the α-and-β- angles shown in the below diagram:

ααα104104104818181βββaaabbb

Video Solution

Step-by-Step Solution

In the question, we can observe that there are two pairs of parallel lines, lines a and b.

When a line crosses two parallel lines, different angles are formed

 

Angles alpha and the given angle of 104 are on different sides of the transversal line, but both are in the interior region between the two parallel lines,

This means they are alternate angles, and alternate angles are equal.

Therefore, 

Angle beta and the second given angle of 81 degrees are both on the same side of the transversal line, but each is in a different position relative to the parallel lines, one in the exterior region and one in the interior. Therefore, we can conclude that these are corresponding angles, and corresponding angles are equal.

Therefore,

Answer

α=104 \alpha=104 β=81 \beta=81

Exercise #11

What is the value of X given that the angles are between parallel lines?

XXX154154154

Video Solution

Step-by-Step Solution

The angle X given to us in the drawing corresponds to an angle that is adjacent to an angle equal to 154 degrees. Therefore, we will mark it with an X.

Now we can calculate:

x+154=180 x+154=180

x=180154=26 x=180-154=26

Answer

26°

Exercise #12

What is the size of the missing angle?

656565

Video Solution

Answer

It cannot be calculated.

Exercise #13

Calculate the angle α \alpha given that the lines in the diagram below are parallel.

ααα40

Video Solution

Answer

40°

Exercise #14

Calculate X given that the lines in the diagram below are parallel.

X70

Video Solution

Answer

110

Exercise #15

Calculate the angle α \alpha given that the lines in the diagram are parallel.

ααα55

Video Solution

Answer

125°

Exercise #16

Calculate the angle α \alpha given that the lines in the diagram below are parallel.

ααα120

Video Solution

Answer

60°

Exercise #17

Calculate angle α \alpha given that the lines in the diagram are parallel.

ααα50

Video Solution

Answer

50°

Exercise #18

The lines shown below are parallel.

Calculate the size of angle α \alpha and indicate the relationship between the two angles.

70

Video Solution

Answer

110, co-interior angles.

Exercise #19

Lines a and b are parallel.

Calculate the size of angle B.

aaabbb100B

Video Solution

Answer

80 80

Exercise #20

Angle 2 is equal to 110 degrees.

Calculate the size of angle 1.

12

Video Solution

Answer

70 70