## Elementary Geometry for College Students (6th Edition)

m$\angle$ 1 = 34$^{\circ}$
Step 1: m$\angle$ 1 + m$\angle$ 2 = m$\angle$ ABC. Step 2: Since m$\angle$ 1 = m$\angle$ 2; Substitute x for m$\angle$ 1, x for m$\angle$ 2, and 68 for m$\angle$ ABC. x + x = 68 Step 3: Simplify the left side of the equation. 2x = 68 Step 4: Divide both sides by 2. $\frac{2x}{2}$ = $\frac{68}{2}$ Step 5: Solve. x = 34. Since x = 34, then m$\angle$ 1 - 34$^{\circ}$.