You're working on a
two-column proof to show that lines
m and
n are parallel, given that
∠1 ≅ ∠2.
Let’s walk through the logic step-by-step and fill in the missing statements and reasons.
---
🧩 Given:
- ∠1 ≅ ∠2
🎯 Goal:
- Prove:
m ∥ n
---
##
✔ Step-by-Step Proof:
We’ll use the
Vertical Angles Theorem and the
Transitive Property of Congruence, then apply the
Corresponding Angles Postulate (or its converse) to conclude the lines are parallel.
---
🔢 Filled-in Two-Column Proof:
|
Statements |
Reasons |
|--------------------------|----------------------------------|
| 1. ∠1 ≅ ∠2 | Given |
| 2. ∠2 ≅ ∠3 | Vertical Angles Theorem |
| 3. ∠1 ≅ ∠3 | Transitive Property of Congruence|
| 4. m ∥ n | Corresponding Angles Converse |
---
## 📚 Explanation:
Step 1: ∠1 ≅ ∠2 — *Given*
This is stated in the problem. We start here.
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Step 2: ∠2 ≅ ∠3 — *Vertical Angles Theorem*
Look at the diagram: ∠2 and ∠3 are vertical angles (they are opposite each other when two lines intersect).
👉
Vertical angles are always congruent.
---
Step 3: ∠1 ≅ ∠3 — *Transitive Property of Congruence*
If ∠1 ≅ ∠2 and ∠2 ≅ ∠3, then by the transitive property, ∠1 ≅ ∠3.
---
Step 4: m ∥ n — *Corresponding Angles Converse*
Now look at ∠1 and ∠3 — they are
corresponding angles formed by the transversal crossing lines m and n.
> 📌
Corresponding Angles Converse Postulate: If two lines are cut by a transversal so that corresponding angles are congruent, then the lines are parallel.
Since ∠1 ≅ ∠3 (corresponding angles), we can conclude
m ∥ n.
---
##
✔ Final Answer:
The completed proof is:
| Statements | Reasons |
|-------------------|----------------------------------|
| ∠1 ≅ ∠2 | Given |
| ∠2 ≅ ∠3 | Vertical Angles Theorem |
| ∠1 ≅ ∠3 | Transitive Property of Congruence|
| m ∥ n | Corresponding Angles Converse |
✔ This proves that lines
m and
n are parallel.
---
Let me know if you’d like to see a diagram explanation or how this connects to other angle relationships!
Parent Tip: Review the logic above to help your child master the concept of parallel lines proofs worksheet answers.