This is math, not English, but okay xD
"Two intersecting lines are perpendicular if and only if they form four 90 degree angles" would be my answer.
Yes some of confucius's idea about people and society are relevant today because he had some great ideas and ways of thinking however some things are no longer acceptable in today's society. like mourning for 3 years over the loss of a parent. Lao-tzu's philosophy is somewhat compatible with the modern world because meditation is still a good for people but other things like gaining wisdom through understanding the universe isn't practical anymore because we know so much more about the universe than we did back in Lao-tzu's time.
Answer:
I honestly dont wanna think about that LOL
To show that you have considered different point of view!!!! AAAPPEXXXXXX