McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
6. Trapezoids and Kites
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Exercise 58 Page 529

One diagonal of a kite is a perpendicular bisector of the other diagonal.

See solution.

Practice makes perfect

We are asked to show that the two shaded triangles are congruent in the kite. Let's mark the congruent sides of the kite.

Point N is equidistant from P and M, and point Q is also equidistant from P and M. According to the Converse of the Perpendicular Bisector Theorem, they are both on the perpendicular bisector of PM. This means that R is the midpoint of PM, so segments PR and MR are congruent.

Since NR is a common side of triangles △ PNR and △ MNR, these two triangles have three pairs of congruent sides. According to the Side-Side-Side (SSS) Congruence Postulate, this means that the two triangles are congruent. △ PNR≅ △ MNR We can summarize the steps above in a two-column proof.

Completed Proof

2 &Given:&& PQMN is a kite & && NP≅NM, QP≅QM &Prove:&& △ MNR≅△ PNR Proof:

Statements
Reasons
1.
NP≅NM
QP≅QM
1.
Given
2.
QN bisects PM
2.
Converse of the Perpendicular Bisector Theorem
3.
RP≅RM
3.
Definition
4.
NR≅NR
4.
Reflexive property of congruence
5.
△ MNR≅△ PNR
5.
SSS