Big Ideas Math Geometry, 2014
BI
Big Ideas Math Geometry, 2014 View details
5. Properties of Trapezoids and Kites
Continue to next subchapter

Exercise 50 Page 406

Consider two kites where the congruent angle is the one between congruent sides. You'll need to consider a concave kite.

No, see solution.

Practice makes perfect

To determine if this congruence theorem is valid or not, let's begin by considering a kite.

Notice that P is equidistant from the endpoints of QS, and similarly, R is equidistant from the endpoints of QS as well. Then, by the Converse of the Perpendicular Bisector Theorem, both P and S lie on the perpendicular bisector of QS.

Then, any point on PR will generate a pair of consecutive congruent sides. Thus, let's consider a point Z on it such that ZQ = QR.

We now have two kites – namey, PQRS and PQZS. Next, let's list the congruent parts between them. ccc RS ≅ ZS & & Side SP ≅ SP & & Side ∠P ≅ ∠P & & Angle PQ ≅ PQ & & Side QR ≅ QZ & & Side Notice that the two kites meet the conditions of the given theorem but they are not congruent because the corresponding angles are not congruent. Therefore, SSASS is not a valid congruence theorem for kites.

Extra

Extra

When the congruent angles are the ones formed by the noncongruent sides, we have that both kites are the same, so they are congruent in this case. However, since we found an example where the SSASS congruence theorem fails, we can claim that it is not valid.