1) ∠E and ∠F are supplementary and ∠F and ∠G are supplementary (given)
2) m∠E+m∠F=180 degrees, m∠F+m∠G=180 degrees (supplementary angles have measures that add to 180 degrees)
3) m∠E=m∠G (subtraction property of equality)
4) ∠E≅∠G (angles with equal measure are congruent)