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# Adjacent Angles - Concept

###### Brian McCall

###### Brian McCall

**Univ. of Wisconsin**

J.D. Univ. of Wisconsin Law school

Brian was a geometry teacher through the Teach for America program and started the geometry program at his school

Adjacent angles share a side and a vertex. If angles only share a side but not a vertex, they are not adjacent. **Adjacent angles** can also be described as "next to" or "side-by-side" angles.

A word we use often in Geometry is this word Adjacent. You're going to use it in the beginning parts of Geometry and then once you get on Trigonometry as well. We'll hold of on adjacent sides for Trigonometry. But for now the key parts of an adjacent angle that they share a vertex, again the vertex is this point right here I'm going to draw a red dot. So this right here is a vertex. They have a side in common which sets them apart from vertical angles. So the side that these two angles share is that ray right there. So I could say that this angle one and two are adjacent because they share a vertex and they have a side in common. Now if you've been really technical, these two have to be coplanar which means that they're on the same plane.

So if I look at this triangle right here where I've drawn in a line segment we only have two adjacent angles. I'm going to write these as 3 and 4. These two angles right here I'll circle them, are not adjacent because they do not share vertex. So you can think of adjacent as kind of a word for next to.

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###### Brian McCall

B.S. in Chemical Engineering, University of Wisconsin

J.D. University of Wisconsin Law School (magna cum laude)

He doesn't beat around the bush. His straightforward teaching style is effective and his subtle midwestern accent is engaging. There's never a dull moment with him.

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## bmath · 4 months, 3 weeks ago

Thx please talk a little slower next time

## saba mahmoud · 6 months, 2 weeks ago

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## saba mahmoud · 6 months, 2 weeks ago

thanks but next time make it little bit slow when you talk but i love it

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