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# Vertical angles

By using our knowledge of supplementary, adjacent, and vertical angles, we can solve problems involving the intersection of two lines. Including this one! Created by Sal Khan.

## Want to join the conversation?

• What is the difference between intercept and intersecting? anyone?
• Intercept and intersect are similar terms used in different math subjects. An intercept, as in x or y intercept, is a term commonly used in graphing, where a line crosses your y or x axis at zero. An intersection is used in geometry, where a line segment or a ray crosses another. Hope this helped!
• How is CEF adjacent () ?
• Adjacent refers to angles that add up to 90 degrees not straight lines. They are not adjacent, They are supplementary.
• What are adjacent, supplementary and complimentary angles? anyone?
• Supplementary angles are two angles whose angle measures sum to 180 degrees. For example, if one angle is 120 degrees and another angle is 60 degrees, the two angles are supplementary. Complementary angles are two angles whose angle measures sum to 90 degrees. For example, if one angle is 30 degrees and another angle is 60 degrees, the two angles are complementary. Adjacent angles share a side, share a vertex, and don't overlap. This link might help you picture adjacent angles. https://www.mathsisfun.com/geometry/adjacent-angles.html
• Can angles be complementary and/or supplementary without being adjacent? Thx in advance
• Yes if you have two parallel lines and a transversal, there are all sorts of supplementary angles (same side interior, same side exterior) that are not adjacent. In a right triangle, the two acute angles will always be complementary. They do not have to even be related to each other in any way, they can be drawn independently.
• So what is exactly a vertical angle?
• It is vertical angles (plural) - a pair of non-adjacent angles formed when two lines intersect. There are two pair of vertical angles with intersecting lines, they are across from each other.
• How are angles:CEA and CEB Adjacent? They aren't connecting to one line..
• The angles CEA and CEB are indeed adjacent. As you can see by looking at the letters they have both C and E. Both angles share a common vertex of E and they also share the line segment of C, therefore, they are touching, or adjacent.
• Are there any tricks to remember complimentary, vertical, and supplementary angles?
• complimentary and supplementary are not quite related to vertical, so you should not put all three together. Vertical angles are across from each other on any two intersecting lines and are always congruent.
If you draw a line across the C, it sort of looks like a 9, so it is two angles adding to be 90, If you draw a line across the S, it sort of looks like an 8 to remind us that it is two angles adding up to 180.
• I still don't get the difference between the verticle angle v.s supplementary & complementary angles.
• vertical angles are very specific - you have two have two intersecting lines to form two sets of vertical angles which are across from each other and congruent.
Both supplementary angles and complementary angles are much broader - they do not even have to be touching or near each other, but they could be.
Any two angles that add to be 90 degrees are complementary. This includes the two angles of a right triangle, any time you put a ray between the two sides of a right angle, or just two angles in two different places.
Similarly, any two angles that add to be 180 degrees is complementary. This includes linear pairs (any two angles that form a line), same side interior, same side exterior, or just any two angles in two different places.