Well the link can be a video from yt. Like it can be related to your questions. Or it’s possible someone is trying to hack just be careful :)
In total that would be 12ft
Divide 200 by 150 which will result in a decimal .75 and then you multiply that by 100 which results in 75 and that is your percentage
C and D because they have had their dimensions altered.
A and B will produce congruent shapes because their dimensions have not been changed