We are trying to find the average speed of the plane, which is mph, or
. Using proportions, we can find the average speed of the plane in mph:

- Use the information from the problem to create a proportion. Remember that we are looking for mph, so we will call that
.

- Multiply the entire equation by


- Divide both sides of the equation by
to clear both sides of the mile unit
The average speed of the plane is 300 mph.
Answer:
D.
Step-by-step explanation:
When a line is perpendicular to another, their slopes will be opposite reciprocal. For example, 1 would be -1, -3 would be
, and
would be -5. The equation is written in slope-intercept form:

m is the slope, so find the equation with the opposite reciprocal of 3,
:
is the only option with the correct slope, so the answer is D.
a the side lengths must be = but only opposite angles must be = it COULD be a square but is could be many other things.