Answer: " y = 30° " .
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Note: The sum total of the measure of all angles lying on a straight
line is 180°.
So; x + y + z = 180 .
Given: x = 2y ;
z = 3y ;
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Find the value of: " y " ;
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Since: x + y + z = 180 ;
Substitute: "2y" for "x" ;
and: "3y" for "z" ;
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2y + y + 3y = 180 ;
6y = 180 ;
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Divide EACH SIDE of the equation by "6" ; to isolate "y" on one side of the equation; and to solve for "y" ;
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6y/ 6 = 180 / 6 ;
y = 30 ;
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Let us check our work;
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2y + y + 3y = 180 ;
Substitute our solved value: "30" ; for "y" ; in the equation; to see if the equation holds true:
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2(30) + 30 + 3(30) =? 180 ?
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60 + 30 + 90 = ? 180 ?
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90 + 90 = ? 180 ? Yes!
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