Question: Given: m∠AEC = 104° and m∠CBD = 31°, Explain why angles ACE, ACB and BCD have a sum of 180°. Use the transversal (line GF) as the basis for your argument.
when you add the first 2 angles up you get 135. Your goal is 180. so you have to figure out the middle one. Which is 45. if you add all of the numbers up they should equal 180.