What is the value of X?
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What is the value of X?
Since alternate angles are equal between parallel lines, they are equal to each other.
Therefore we can say that:
We will move X to the right side and keep the plus and minus signs accordingly when making the change:
X=70
Does the drawing show an adjacent angle?
Look for the Z-pattern! Alternate interior angles are on opposite sides of the transversal (the diagonal line) and between the parallel lines. They form a Z-shape when you trace from one angle to the other.
When a transversal crosses parallel lines, it creates the same angle relationships at both intersections. Think of it like sliding one intersection down to the other - the angles match perfectly!
Check your algebra! From , subtract X from both sides to get . Don't subtract 20 from both sides first - that leads to the wrong answer.
Substitute X = 20 back into both expressions: and . Both angles should be equal since they're alternate interior angles!
If the lines weren't parallel, alternate interior angles would not be equal, and you couldn't solve for X with the given information. Parallel lines are essential for this angle relationship to work.
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