How can Daniela get m∠1 and m∠3 to both equal the same expression?
She can subtract m∠2 from both sides of m∠1 + m∠2 = 180° and m∠2 + m∠3 = 180°.
She can subtract m∠1 from both sides of m∠1 + m∠2 = 180°, and subtract m∠3 from both sides of m∠2 + m∠3 = 180°.
She can subtract 180° from both sides of m∠1 + m∠2 = 180° and m∠2 + m∠3 = 180°.
She can measure m∠1 and m∠3 with a protractor.