How can you prove a triangle is an equilateral triangle?
a. use the distance formula to see if at least two sides are congruent.
b. use the slope formula to see if any sides are perpendicular.
c. use the distance formula to see if all three sides are congruent.
d. use the slope formula to see if any sides are parallel.

77

step-by-step explanation:

- "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."