if a + a = 90, then a = 45

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

• a = 45,

  if the following are true:

  • a = b
  • b = c

  then a = c

  • a = 90 / 2,

    if a ⋅ b = c, then a = c / b

    • a ⋅ 2 = 90,

      if a + a = b, then a ⋅ 2 = b

      • a + a = 90
  • 90 / 2 = 45, 90 / 2 = 45