Math Problem Statement

Reorder the steps of the proof to make sure that steps that are logically dependent on prior steps are in the proper order.

Given: EE is the midpoint of start overline, B, D, end overline BD and angle, A, B, C, \cong, angle, C, D, F, .∠ABC≅∠CDF.

Prove: start overline, B, D, end overline, is perpendicular to, start overline, C, E, end overline BD ⊥ CE .

Solution

To reorder the steps of the proof logically, let's carefully analyze what needs to be proven and the given information:

Given:

  1. EE is the midpoint of BD\overline{BD}.
  2. ABCCDF\angle ABC \cong \angle CDF.

To Prove:

  • BDCE\overline{BD} \perp \overline{CE}.

Proof Steps

Step 1: Show EE as the midpoint of BD\overline{BD}

Since EE is the midpoint of BD\overline{BD}, we know that: BE=ED.BE = ED.

Step 2: Use congruent angles

Given ABCCDF\angle ABC \cong \angle CDF, we know that these angles have equal measure: mABC=mCDF.m\angle ABC = m\angle CDF.

Step 3: Establish congruent triangles

Consider triangles ABE\triangle ABE and CDE\triangle CDE.

  • BE=EDBE = ED (from midpoint property).
  • ABCCDF\angle ABC \cong \angle CDF (given).
  • CE\overline{CE} is shared between the two triangles.

By SAS (Side-Angle-Side) Congruence, we conclude that: ABECDE.\triangle ABE \cong \triangle CDE.

Step 4: Conclude perpendicularity

Since ABECDE\triangle ABE \cong \triangle CDE, corresponding parts of congruent triangles are equal. Therefore, BEC=90\angle BEC = 90^\circ. This implies: BDCE.\overline{BD} \perp \overline{CE}.

Final Proof Sequence

The reordered proof follows logically as:

  1. Show EE as the midpoint of BD\overline{BD}.
  2. Use the congruent angles ABCCDF\angle ABC \cong \angle CDF.
  3. Prove ABECDE\triangle ABE \cong \triangle CDE by SAS.
  4. Conclude BDCE\overline{BD} \perp \overline{CE} by showing BEC=90\angle BEC = 90^\circ.

Would you like further details on any of the steps?


  1. What is the definition of midpoint and how is it used in proofs?
  2. How does congruence in triangles help in establishing perpendicularity?
  3. What other methods could prove lines are perpendicular?
  4. How does SAS congruence apply to different triangles in proofs?
  5. What properties of right angles can help simplify proofs involving perpendicular lines?

Tip: In proofs involving congruent angles, look for opportunities to use triangle congruence criteria like SAS, ASA, or SSS to establish relationships.

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Math Problem Analysis

Mathematical Concepts

Geometry
Triangle Congruence
Midpoint
Perpendicular Lines

Formulas

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Theorems

SAS Congruence
Properties of Midpoints
Right Angle Definition

Suitable Grade Level

Grades 10-12