Which of the following best describes a circle? apex question

In the coordinate plan (-6,9) b (3,9) c (3,3) def is shown in the coordinate plan below

The tiles below are pieces of a normal ecg tracing representing a little less than two heartbeats at a resting rate of 80 bpm. arrange the tiles in their correct order. rank from first to last. do not overlap any tiles.

What is the slope of the line shown below?