Question

Which statement must be true to prove m∠1+m∠2+∠3 = 180?

A. m║n
B. m∠1+m∠2 = 180°-m∠3
C. m∠1+m∠2 = 90°
D. m∠1+m∠2 = m∠3

Answer 1

To prove m∠1 + m∠2 + ∠3 = 180, we can use the fact that the sum of the angles in a triangle is always 180 degrees. The statement that must be true to prove the equation is option B: m∠1 + m∠2 = 180° - m∠3.

Step-by-step explanation:

To prove m∠1 + m∠2 + ∠3 = 180, we can use the fact that the sum of the angles in a triangle is always 180 degrees.

Since we are given m∠1 and m∠2, we can substitute these angles into the equation:

m∠1 + m∠2 + ∠3 = m∠1 + m∠2 + (180 - m∠1 - m∠2) = 180

Therefore, the statement that must be true to prove the equation is option B: m∠1 + m∠2 = 180° - m∠3.