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# Missing angles with a transversal

CCSS.Math:

## Video transcript

let's say that we have two parallel lines so that's one line right over there and then this is the other line that is parallel to the first one I'll draw it as parallel as I can so these two lines are parallel so I'll this is the symbol right over here to show that these two lines are parallel and then let me draw a transversal here so let me draw a transversal this is also a line now let's say that we know that this angle right over here is 110 degrees what other angles can we figure out here well the first thing that we might realize is that look corresponding angles are equivalent this angle the angle between this parallel line and the transversal is going to be the same as the angle between this parallel line of the transversal so this right over here is also going to be 110 degrees now we also know that vertical angles are equivalent so this is 110 degrees then this angle right over here on the opposite side of the intersection is also going to be 110 degrees and we could use that same logic right over here to say that if this is 110 degrees and this is also 110 degrees we could have also said that look this angle right over here corresponds to this angle right over here so that they also will have to be the same now what about these other angles so this angle right over here it's outside ray I guess you could say for is forms aligned with this angle right over here this pink angle is supplementary to this 110 degree angle so this pink angle plus 110 is going to be equal to 180 or we know that this pink angle is going to be 70 degrees and then we know that it achill angle it's a vertical angle with this angle right over here so this is also 70 degrees this angle that's kind of right in below this parallel line with the transversal at the bottom left I guess you could say corresponds to this bottom left angle right over here so this is also 70 degrees and we could have also figured that out by saying hey this angle is supplementary to this angle right over here and then we could use multiple arguments the vertical angle argument the supplementary argument two ways or the corresponding angle argument to say that hey must be 70 degrees as well