Question

Given: <1 and <2 are supplementary, and <2 and <3 are supplementary.
Prove: <1 is congruent <3
By definition of supplementary angles, m<1 + m<2=_____ (a.) and m<2=m<3=_______ (b.) Then, m<1+ m<2= m<2=m<3 by the________ (c.) Subtract m<2 from each side. You get m<1=____ (d.) or <1 congruent_____ (e.)