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| Question 1170173:  I have two right triangles that are connected at point x. On the right, there is triangle one which has point v at the top, w at the corner, and x which connects to triangle two which has point z at the bottom, connected to y which connects to x.
 I am given that line WV is perpendicular to line WY. I am also given that line ZY is perpendicular to line WY, as well as line WV is congruent to ZY. I am supposed to prove that the triangles are congruent and X is the midpoint of line VZ.
 I do have a 4th statement that I attempted to do. That is that angle W is congruent to angle Y because of the def. of perpendicularity. I also have about half of the fifth statement which is that angle 1 and angle 2 are congruent. I don't know how to prove this with reason. I need help.
 Answer by CPhill(1987)
      (Show Source): 
You can put this solution on YOUR website! Absolutely! Let's break down this geometry proof step-by-step. **Given:**
 * Triangle VWX and Triangle YXZ
 * WV ⊥ WY
 * ZY ⊥ WY
 * WV ≅ ZY
 **To Prove:**
 1.  Triangle VWX ≅ Triangle YXZ
 2.  X is the midpoint of VZ
 **Proof:**
 Here's the breakdown of the proof with reasons:
 1.  **Statement:** WV ⊥ WY
 **Reason:** Given
 2.  **Statement:** ZY ⊥ WY
 **Reason:** Given
 3.  **Statement:** ∠W and ∠Y are right angles.
 **Reason:** Definition of perpendicular lines.
 4.  **Statement:** ∠W ≅ ∠Y
 **Reason:** All right angles are congruent.
 5.  **Statement:** WV ≅ ZY
 **Reason:** Given
 6.  **Statement:** ∠WX V ≅ ∠YX Z
 **Reason:** Vertical angles are congruent.
 7.  **Statement:** Triangle VWX ≅ Triangle YXZ
 **Reason:** Angle-Angle-Side (AAS) Congruence Theorem. (We have ∠W ≅ ∠Y, ∠WX V ≅ ∠YX Z, and WV ≅ ZY)
 8.  **Statement:** VX ≅ XZ
 **Reason:** Corresponding Parts of Congruent Triangles are Congruent (CPCTC)
 9.  **Statement:** X is the midpoint of VZ
 **Reason:** Definition of a midpoint (a point that divides a segment into two congruent segments).
 **Explanation of Step 6:**
 * When two lines intersect, the angles opposite each other at the intersection point are called vertical angles.
 * Vertical angles are always congruent.
 * In this case, line VX intersects line ZY at point X, creating ∠WX V and ∠YX Z, which are vertical angles.
 **In summary, here is the proof in a table format:**
 | Statement | Reason |
 |---|---|
 | 1. WV ⊥ WY | Given |
 | 2. ZY ⊥ WY | Given |
 | 3. ∠W and ∠Y are right angles | Definition of perpendicular lines |
 | 4. ∠W ≅ ∠Y | All right angles are congruent |
 | 5. WV ≅ ZY | Given |
 | 6. ∠WX V ≅ ∠YX Z | Vertical angles are congruent |
 | 7. Triangle VWX ≅ Triangle YXZ | AAS Congruence Theorem |
 | 8. VX ≅ XZ | CPCTC |
 | 9. X is the midpoint of VZ | Definition of a midpoint |
 
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