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Vertical angles worksheets

When two straight lines cross, the angles opposite each other are equal. These free printable worksheets draw the crossing and mark one angle x — the answer is the angle across from it, not a subtraction.

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Vertical angles
Vertical angles worksheet — Two crossing lines, free printable with answer key

The answer key prints on a separate page.

What's on this sheet

Vertical angles are the case children get wrong on the mixed angle-pair page, because the answer is the number they were given rather than something taken away from it. Drilling them alone is how that instinct gets corrected: read the angle across the crossing and copy it.

Why this sheet works

Each figure shows two full lines crossing at a point, so four angles are formed and the two facing pairs are equal. The instruction and the figure agree that no arithmetic is needed, which is the whole lesson — a page where every answer required a subtraction would teach subtraction, not angle facts.

How this one works

One question from this sheet, worked through a step at a time.

Vertical angles

136°andx
opposite=equal
136°→136°
  1. Two straight lines crossing. This is the pair that is NOT a subtraction — nothing adds to 90 or 180 here, so reaching for either is the mistake.
  2. Angles opposite each other at a crossing are EQUAL. Each one is what is left when the same straight line is taken away from the same straight line, so they cannot differ.
  3. So x is 136° — the same as the one across from it, not 180 minus it.

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