## Elementary Geometry for College Students (5th Edition)

$\angle$7 and $\angle$8 are not congruent.
In this diagram the measures of angles 7 and 8 are unknown. The two right angles have no measurable relationship to angles 7 and 8. Although all four angles will equal 360$^{\circ}$, you still don't know the measures of angles 7 and 8.