Special Angle Pairs Notes - Lindsay Bowden - Free Printable

Let's solve each of the 12 problems on this "Special Angle Pairs Practice" worksheet. The goal is to identify each marked angle pair as:

- Complementary (C): Two angles that add up to 90°
- Supplementary (S): Two angles that add up to 180°
- Vertical (V): Angles opposite each other when two lines cross
- Adjacent (A): Angles that share a vertex and a side but do not overlap
- Linear Pair (LP): Adjacent angles that form a straight line (i.e., supplementary and adjacent)

We’ll go through each one carefully.

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1.

Two angles sharing a common vertex and side, forming a "corner" shape with three rays.

- They are adjacent (share a side and vertex)
- Not vertical (not opposite)
- Not linear pair (don’t form a straight line)
- No degree measures → can't check complementary/supplementary

✔ Answer: A

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2.

Two intersecting lines, with two dots marking angles across from each other.

- These are vertical angles (opposite angles formed by intersecting lines)
- Vertical angles are always equal
- Not adjacent or linear pairs
- Can't determine if they're C or S without measures

✔ Answer: V

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3.

Two angles at the same vertex, sharing a side; one appears to be above the other.

- They are adjacent (share a vertex and side)
- Do they form a straight line? No — not a linear pair
- No measure given → can't tell if C or S

✔ Answer: A

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4.

Two intersecting lines, with two dots marking angles on opposite sides.

- These are vertical angles (opposite each other)
- So, V

✔ Answer: V

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5.

Right angle (90°) split into two angles: one labeled with a dot, another ray going diagonally.

- One angle is part of the right angle, so the two angles together make 90°
- Therefore, they are complementary (C)
- Also, they are adjacent (share a side and vertex)
- Not vertical, not linear pair (since sum is 90°, not 180°)

✔ Answer: C, A

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6.

Three rays from a point: one vertical, one horizontal, one diagonal. Dots mark two angles near the intersection.

- The angles appear to be adjacent (they share a side)
- But do they form a straight line? Not clearly.
- They are not vertical (not opposite)
- Without measures, we can’t say C or S
- But note: one angle might be between vertical and diagonal, the other between diagonal and horizontal?

Wait — actually, both angles are adjacent and share a ray, but likely not supplementary unless they make a straight line.

But looking closely: the two marked angles are next to each other, and their non-shared sides form a larger angle. Not necessarily linear.

So only adjacent

✔ Answer: A

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7.

Two angles shown: one is 72°, the other 18°

- 72 + 18 = 90° → Complementary (C)
- Are they adjacent? Yes — they share a side and vertex
- Do they form a straight line? No → not linear pair
- Not vertical (not opposite)

✔ Answer: C, A

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8.

Several rays from a point. Two dots mark two angles next to each other.

- They share a side and vertex → adjacent (A)
- Do they form a straight line? No
- Not vertical
- No measures → can't say C or S

✔ Answer: A

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9.

Two angles at a vertex, sharing a side. One ray goes left-up, one right, and a third ray in between.

- The two angles are adjacent (share a side)
- Do they form a straight line? Possibly — but the outer rays don’t seem to form a straight line.
- Wait: the figure shows two rays extending from the vertex — one going down-right, one up-left, and a middle ray.
- The two marked angles are on the same side of the middle ray.
- They may be adjacent, but not forming a straight line.
- Without measures, no C or S

✔ Answer: A

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10.

Two angles at a vertex, one large, one small, forming a straight line.

- The two angles form a straight line → linear pair (LP)
- Linear pairs are always supplementary (S) → sum to 180°
- Also adjacent (share a side and vertex)

✔ Answer: S, LP, A

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11.

Two intersecting lines, with two dots marking opposite angles.

- These are vertical angles → V
- Also, since they’re opposite, not adjacent
- Not linear pair

✔ Answer: V

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12.

Two separate angles shown: one is 50°, the other 130°

- Are they related? They don’t share a vertex or side → not adjacent
- Not vertical
- Not linear pair
- But 50° + 130° = 180° → Supplementary (S)

Even though they’re not connected, the problem says “marked angle pair” — so if both are marked and we're to classify them based on relationship.

But since they’re not adjacent, not vertical, not linear pair, but sum to 180°, they are supplementary

✔ Answer: S

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✔ Final Answers:

| # | Answer |
|---|--------|
| 1 | A |
| 2 | V |
| 3 | A |
| 4 | V |
| 5 | C, A |
| 6 | A |
| 7 | C, A |
| 8 | A |
| 9 | A |
| 10 | S, LP, A |
| 11 | V |
| 12 | S |

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🔍 Explanation Summary:

- Complementary (C): Sum to 90° → #5, #7
- Supplementary (S): Sum to 180° → #10, #12
- Vertical (V): Opposite angles from intersecting lines → #2, #4, #11
- Adjacent (A): Share a vertex and side → #1, #3, #5, #6, #7, #8, #9, #10
- Linear Pair (LP): Adjacent angles forming a straight line → #10

> Note: Some answers have multiple correct classifications (e.g., #5: C and A; #10: S, LP, A).

Let me know if you'd like a printable version or a key!