Dedicated Quant Strategies Session 8 question - how do we know the distance between two points w/o any such info int

GRE Quant Problem Solving
1

Hello! In the question image attached, how we do we know that the distance between Q and R is the same as the radius of each of these semicircles? Visually it makes sense but what info do we have in the question to infer that? Since these diagrams aren’t drawn to scale, not sure if we’re going by assumption or if there’s anything in the question or definitions that help us conclude this?

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image1920×1080 141 KB

Thanks!

2

PQ= radius = 5
PR= diameter=2r=2*5=10
QR=PR-Pq=10-5=5

3

Thanks :slight_smile: hope I don’t make this kind of mistake on exam day