<em><u>The equation can be used to find the actual length of Gregory's room is:</u></em>

<em><u>Solution:</u></em>
Given that,
The scale that he uses is:
1 cm : 4 feet
On this drawing, the room is 3 cm long
Let "x" be the actual length of room
Therefore,
1 cm : 4 feet
3 cm : "x" feet
This forms a proportion. Therefore,

Therefore, Option C is correct
Given that,
Rob chose A as the correct answer. Which is,

But option A is wrong
So, Rob made a mistake in measuring the equivalent ratio, it should be 
Answer:
-3/2
Step-by-step explanation:
One can read off the slope of the given line directly from the graph. As x increases by 3, y increases by 2. Thus, the slope of the given line is
m = rise / run = 2 / 3
Any line perpendicular to this given line has a slope which is the negative reciprocal of the slope previously found:
-1 3
Slope of perpendicular line = ------------ = - -----
2/3 2
This matches the first of the given possible answer choices.
This is the answer yeah I not sure but I saw it somewhere
To solve this problem you must apply the proccedure shown below:
1. The vertex i at <span>(0, 36) and a focus at (0, 39), then you have:
a=36
a^2=1296
2. The directrix is:
y=a^2=c
c=39
y=1296/39
</span>y=432/13<span>
Therefore, the answer is the option D, which is: </span><span>D. y=± 432/13</span>