Answer:
1) Parallel lines are "ALWAYS"
coplanar.
2) Perpendicular lines ARE "ALWAYS"
coplanar.
3) Distance around an unmarked circle CAN "NEVER" be measured
Step-by-step explanation:
1) Coplanar means lines that lie in the same plane. Now, for a line to be parallel to another line, it must lie in the same plane as the other line otherwise it is no longer a parallel line. Thus, parallel lines are always Coplanar.
2) similar to point 1 above, perpendicular lines are Coplanar. This is because perpendicular lines intersect each other at right angles and it means they must exist in the same plane for that to happen. Thus, they are always Coplanar.
3) to have the distance, we need to have the circle marked out. Because it is from the marked out circle that we can measure radius, diameter and find other distances around the circle. Thus, distance around an unmarked circle can never be measured.
First we find the measurement of dark dot .
ANd for that we have to use the formula of the angle formed by the intersection of chord .
Let the dark dot be t.
So we have

t and z are linear pair and sum of angles of linear pair =180 degree.
So we get

I'm sorry the picture is blurry. Could you post another one.
C = 10m + 30, where C is total cost and m is # of months
C = 10(5) + 30
C = 50 + 30
C = $80
$160 = 10m + 30
160 - 30 = 10m
130/10 = m
m = 13 months
Hope that helps