if the following are true:

• ((a + a) + a) + a = 360
• not (4 = 0)

then a = 90

Start from the conclusion and work back up the proof. Click the arrow to show the parents.

• a = 90,

  if the following are true:

  • a = b
  • b = c

  then a = c

  • 360 / 4 = 90, 360 / 4 = 90
  • a = 360 / 4,

    if the following are true:

    • a ⋅ b = c
    • not (b = 0)

    then a = c / b

    • not (4 = 0)
    • a ⋅ 4 = 360,

      if the following are true:

      • a = b
      • a = c

      then b = c

      • ((a + a) + a) + a = 360
      • ((a + a) + a) + a = a ⋅ 4, ((a + a) + a) + a = a ⋅ 4