99 points! given: ∠abc ≅ ∠def and ∠ghi ≅ ∠def prove: m∠abc = m∠ghi assemble the proof by dragging tiles to the statements and reasons columns. angles: ≅ = ∠abc ∠def ∠ghi m∠abc m∠ghi and reasons : given symmetric property transitive property definition of ≅ angles

∠ABC ≅ ∠DEF              - given
∠GHI ≅ ∠DEF               - given
∠DEF ≅ ∠GHI               - symmetric property
∠ABC ≅ ∠GHI               - transitive property 
m∠ABC = m∠GHI          - definition of ≅ angles

We are given that angle ABC and angle DEF are congruent, and that angle GHI and angle DEF are congruent. By the reflexive property of congruence, the measure of angle ABC is equal to the measure of angle DEF, and the measure of angle GHI is equal to the measure of angle DEF. By the substitution property, the measure of angle ABC is equal to the measure of angle GHI.
Hope that helped :)