Which of the following best describes a line?
a. the set of all points in a plane that are equidistant from two points.
b. the set of all points in a plane that are equidistant from three points.
c. the set of all points in a plane that are equidistant from a given point and a given line.
d. the set of all points in a plane at a given distance from a given point.

The correct answer is C

Step-by-step explanation:

The set of all points in a plane that are equidistant from two points. Explanation: The set of all points in a plane that are equidistant from a given point and a given line is a parabola.

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."