(Jon of the Clue Crew shows a line segment sweeping out a circle on the monitor.)  Euclid's third postulate tells us that from any line segment, a circle can be drawn with one endpoint as the center & the segment itself as this line
When drawing evidence from literary and informational texts per Writing standard 
9 ... No set of grade-specific standards can fully reflect the great variety in abilities
, needs ...... An angle is measured with reference to a circle with its center at.