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 31 Page 527

See solution.

Practice makes perfect

We are asked to write a paragraph proof of the following theorem.

Theorem 6.25

If a quadrilateral ABCD is a kite, then its diagonals are perpendicular.

First, let's draw kite ABCD. In a kite there are two pairs of congruent sides. Let's mark them in our graph.

The diagonals of kite ABCD are BD and AC. We want to show that they are perpendicular. First, point A is equidistant from B and D, and point C is also equidistant from B and D. AB & = AD BC &= CD According to the Converse of the Perpendicular Bisector Theorem, points A and C are on the perpendicular bisector of BD.

Diagonal AC lies on the perpendicular bisector of BD. This tells us that it is perpendicular to diagonal BD.

Paragraph Proof

Let's summarize the proof in one paragraph.

2 &Given:&& ABCD is a kite & && AB≅AD,CB≅CD &Prove:&& AC⊥BD

Proof: Both A and C are equidistant from B and D, so according to the converse of the Perpendicular Bisector Theorem, they are both on the perpendicular bisector of BD. This means that diagonal AC is perpendicular to diagonal BD.