Circles - Contradictory Information?

[Stephanie.papes]

I may be missing an underlying concept, but with respect to geometry/circles:

GRE Practice Test #1 in the ETS Official Book (2nd Ed), page 414 #3: Shows diameter of a circle and 2 chords, one on either side, in a quant comparison. Solution says the diameter of the circle > the mean of the lengths of the two chords.

Manhattan GRE Guide Geometry Book, p. 192, #11: Seems to be the same problem, but solution says the answer is D, cannot be determined. Manhattan solution seems more intuitive, but obviously would defer to ETS answer in a testing scenario, unless I am not understanding something?

Thanks in advance

[tommywallach]

Hey Stephanie,

Not quite! The question you described from the GRE averaged the two chords that are not the diameter. The question in our book averages the diameter and one of the chords! Very different!

Make sense?

-t