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Vertical angles review

Review the basics of vertical angles, and try some practice problems.

Vertical angles

Vertical angles are angles opposite each other where two lines cross.
For example, AXD and BXC are vertical angles in the following diagram:
Want to learn more about vertical angles? Check out this video.

Practice set

Problem 1A
Are APD and CPB vertical angles?
All segments that appear straight are straight.
Choose 1 answer:

Want to try more problems like this? Check out this exercise.

Use vertical angles to find a missing angle measure

Let's look at an example.
What is the measure of angle x?
First, let's find the measure of the pink angle:
The pink and blue angles add up to 180 because they are adjacent and form a straight line.
pink angle=180121=59
The pink and green angles also add up to 180 because they are adjacent and form a straight line too.
green angle=18059=121
The measure of angle x=121.

Practice

Problem 2A
What is the measure of angle x?
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi

Want to try more problems like this? Check out this exercise.

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