## Geometry: Common Core (15th Edition)

Let $\angle A$ be the angle. Write and solve an equation. $m\angle A+(m\angle A-52)=90\longrightarrow$ definition of complement $2m\angle A - 52=90\longrightarrow$ combine like terms $2m\angle A=142\longrightarrow$ addition property of equality $m\angle A=71\longrightarrow$ division property of equaliity