header bg

Question:

If XY=YZ and angle Y measures 90 degrees in the figure above, which of the following CANNOT be concluded?

A XZ
Explaination

Here we are looking for the choice that is NOT true. Since the triangle is isosceles (XY=YZ), then a=b=45. This means that a+b=90. So answers (A) and (C) must be true.
For all right triangles, the Pythagorean Theorem applies, so (D) is also true.
Answer (B) is the correct answer because it is NOT true that XZ