EXAMPLE 1 Apply the Base Angles Theorem

SOLUTION

In DEF, DE DF . Name two congruent angles.

DE DF , so by the Base Angles Theorem, E F.

GUIDED PRACTICE for Example 1

SOLUTION

Copy and complete the statement.

1. If HG HK , then ? ? .

HGK HKG

GUIDED PRACTICE for Example 1

Copy and complete the statement.

If KHJ KJH, then ? ? .If KHJ KJH, then ? ? .2. 2.

SOLUTION

If KHJ KJH, then , KH KJ