## Geometry: Common Core (15th Edition)

The labeled angle form a corresponding angle pair. The corresponding angle theorem tells us they are congruent, so they have the same measure. $3x-10=x+40\longrightarrow$ definition of congruent $2x-10=40\longrightarrow$ subtraction property of equality $2x=50\longrightarrow$ addition property of equality $x=25\longrightarrow$ division property of equality Substitute to find the angle measures. $3x-10=3(25)-10=75-10=65$ $x+40=25+40=65$