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If l||m and the measure of angle 7 is twice the measure of angle 2, then the measure...

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lnj100 | Student, Grade 10 | Valedictorian

Posted June 11, 2013 at 2:59 PM via web

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If l||m and the measure of angle 7 is twice the measure of angle 2, then the measure of angle 7 is?

 

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embizze | High School Teacher | (Level 1) Educator Emeritus

Posted June 11, 2013 at 3:13 PM (Answer #1)

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I assume that we have two lines, l and m, that are parallel. The lines are cut by a transversal t creating 8 numbered angles. Since angle 2 and angle 7 are not congruent, they must be supplementary.

Then `m/_2+m/_7=180`

But we know `m/_7=2m/_2` Substituting we get:

`m/_2+2m/_2=180`

`3m/_2=180`

`m/_2=60`

`==>m/_7=120`

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The measure of angle 7 is 120 degrees.

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