Angles in Parallel Lines: Using variables

The angles below are formed between two parallel lines.

Calculate the value of X.

Since the angle equal to 20 and the angle 2x are alternate angles, they are equal to each other.

Therefore:

$2x=20$

We divide both sections by 2:

$\frac{2x}{2}=\frac{20}{2}$

$x=10$

$10$

What is the value of X?

Since alternate angles are equal between parallel lines, they are equal to each other.

Therefore we can say that:

$x+20=2x$

We will move X to the right side and keep the plus and minus signs accordingly when making the change:

$20=2x-x$

$20=x$

X=70

What is the value of X?

40

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

10

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

2

Calculate X and the indicated angles, if possible.

2

Calculate X given that the lines in the drawing are parallel.

154/101

Calculate X and the indicated angles, if possible.

15

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

20

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

80

Calculate X.

20

The lines a and b are parallel.

Calculate the value of X.

25.6

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

27°

Calculate X and the value of the marked angles, if possible.

40

What is the value of X?

35

Lines a and b are parallel.

x = ?

28.5

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

22

Calculate X.

10

Calculate X.

45

Calculate X and the marked angles.

14