Pearson Geometry Common Core, 2011
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Pearson Geometry Common Core, 2011 View details
4. Using Corresponding Parts of Congruent Triangles
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Exercise 19 Page 247

You will need the Vertical Angles Theorem.

See solution.

Practice makes perfect

Let's begin by analyzing the desired outcome of our proof. We want to show that KQ bisects JP. Notice that JM and PM will be congruent if we prove that △ KJM and △ QPM are congruent. Then, point M would be the midpoint, and hence KQ would bisect JP. We are given that JK ≅ PQ. This is how we will begin our proof! Statement1)& JK ≅ PQ Reason1)& Given We are also given that JK ∥ QP. Therefore, if we draw the lines passing through these sides, then we will get two parallel lines a and b. If we also draw a line passing through the side KQ, then we will get a transversal t that intersects these parallel lines.

Notice that ∠ JKM and ∠ PQM are alternate interior angles. Lines a and b are parallel, thus by the Alternate Interior Angles Theorem ∠ JKM ≅ ∠ PQM. Statement 2)& ∠ JKM ≅ ∠ PQM Reason 2)& Alternate Interior Angles & Theorem Next, we can tell that ∠ KMJ and ∠ QMP are vertical angles.

Therefore, by the Vertical Angles Theorem, these angles are congruent. Statement 3)& ∠ KMJ ≅ ∠ QMP Reason 3)& Vertical Angles Theorem Now, we know that two angles and a non-included side of △ KJM are congruent to two angles and a non-included side of △ QPM. Therefore, by the Angle-Angle-Side (AAS) Congruence Theorem, △ KJM ≅ △ QPM. Statement4)& △ KJM ≅ △ QPM Reason4)& AAS Theorem Corresponding parts of congruent triangles are congruent. Therefore, JM ≅ PM. Statement5)& JM ≅ PM Reason5)& Corresponding parts of & congruent triangles are & congruent. Since JM ≅ PM, we can conclude that the point M is the midpoint of JP. Hence, KQ bisects JP. Statement6)& KQ bisects JP Reason6)& Definition of a segment bisector

Completed Proof

Statements
Reasons
1.
JK ≅ PQ
1.
Given
2.
∠ JKM ≅ ∠ PQM
2.
Alternate Interior Angles Theorem
3.
∠ KMJ ≅ ∠ QMP
3.
Vertical Angles Theorem
4.
△ KJM ≅ △ QPM
4.
AAS Theorem
5.
JM ≅ CPM
5.
Corresponding parts of congruent triangles are congruent.
6.
KQ bisects JP
6.
Definition of a segment bisector