$\angle EIG\cong\angle FIH$ $\angle EIF\cong\angle GIH$
Work Step by Step
Theorem 2.4 tells us that right angles are congruent. Both $\angle EIG$ and $\angle FIH$ are marked as right angles. Theorem 2.3, the Congruent Complements Therorem, tells us that angles that are complements of the same angle are congruent. $\angle EIF$ and $\angle GIH$ are both complements of $\angle FIG$.