URGENT If m<2+m<3+m<4=180* then prove that m<1=m<3+m<4

Question

A m<2 + m<3 + m<4 = 180*

B m<1 + m<2 =180*

C m<1 + m<2 = m<2 + m<3 + m<4

D m<1 + m<2 - m<2 = m<2 +m<3 + m<4 - m<2

E m<1 = m<3 + m<4

Answer 1

Yes, your proof is correct;

However, you should supply the REASONS

angle 2 + angle 3 + angle 4 = 180 <---- GIVEN

angle 1 + angle 2 = 180 <--- given

angle 1 + angle 2 = angle 2 + angle 3 + angle 4 <--- substitution/ transitive

angle1 + angle 2 - angle 2 = angle 2 + angle 3 + angle 4 - angle 2 <--- subtracts angle 2 from both side

angle 1 = angle 3 + angle 4