Answer:
Midpoint
Step-by-step explanation:
The midpoint is the point on the segment halfway between the endpoints. It may be the case that the midpoint of a segment can be found simply by counting. If the segment is horizontal or vertical, you can find the midpoint by dividing the length of the segment by 2 and counting that value from either of the endpoints.
Pi is 3.14
1st # is 3.13
2nd # is 3.15
These numbers are irrational because pi=infinity
( I am not exactly sure if this is right so don't blame me if you get this wrong, I just tried to help.....) :T
<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 
Earth: radius = 6378 kilometer, diameter = 12756 kilometers.
It is C because a and b are zeros