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# Constructing angles

CCSS.Math:

## Video transcript

we're asked to construct a 10 degree angle so they give us we have this little angle tool here that we can use to construct to construct an angle so this like that and then we gave us a give us a protractor to actually measure the angle so let's set it up let's put the protractor here let's put the vertex of the angle at the center of the protractor or another way to the center of the protractor at the center that vertex looks like the protractor is a little bit easier to manipulate so let's do that there now let's put one of the Rays let's put one of the Rays here at zero degrees and now I'm going to put the other ray at 10 degrees and it looks like I am done I have constructed a 10 degree angle and you want to be careful here when you use this tool because the angle in question let me remove the protractor show you what I'm talking about that this right over here is the angle that we're talking about if I had switched these two rays the way the tool is set up it might have viewed interpreted the angle as this outer angle right over here so be careful to to look at which angle were actually measuring but look this looks like I did the 10 degree angle so let me check my answer and just to be clear what I'm talking about if you did the 10 degree angle like this like this that it probably or definitely would have marked it wrong even though the interior angle right over here or this this angle right over here might be 10 degrees the way the tool is set up you see from this circle that it thinks that you're looking at this outer angle so it's important to make sure at least for this the sake of this exercise too that this that the system that the computer program knows which angle you're going to talk about let's do one more of these one hundred and fifty five degree angle this one's interesting because this is an obtuse angle so once again let us put the protractor at the at the vertex of the angle so just like that and now that seems pretty good now let's take one ray and put it at zero degrees and then let's take the other one and put it at 155 so once again 10 20 30 40 50 60 70 80 90 that gets us to a right angle then we're start getting into obtuse angles 100 10 120 130 140 150 and I'm just to make sure that blue arc is measuring this angle right over here not the outer one and let me move the protractor out of the way so we can get a good look at it and we got it wrong so let's see what we owe one hundred and fifty five degree angle not one hundred fifty degree angle let me fix that one hundred and fifty five degree angle now we got it right