I used to visit a park quite close to our home when I was younger it had lots of plants and birds were always chirping .it was usually crowded and trees surrounded the area and the park instruments such as swings and slides were in perfect condition
I visited that place again after 5years and it’s change broke my heart .the plants and trees were either dead or dying no one maintained them ,no one was. Around ,the area was littered with plastics and thermocouple and the trees had all been cut down soo the area was very hot , the swings and slides were dirty and rusted
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.
