Short Answer 
The properties of isosceles trapezoids ensure congruent legs and base angles. By identifying congruent elements and applying the SAS congruence criterion, it is concluded that triangles FHE and GEH are congruent, denoted as ŒiFHE ‚aO ŒiGEH.
Step 1: Understand the Properties of Isosceles Trapezoids
In an isosceles trapezoid, such as EFGH, the legs (sides FE and GH) are congruent. This property stems from the definition of an isosceles trapezoid, which ensures that the two non-parallel sides are of equal length. Additionally, the base angles FHE and GEH are also congruent due to the base angle theorem for isosceles trapezoids.
Step 2: Identify the Congruent Elements in the Triangles
Triangles FHE and GEH share a common side, EH, which is self-congruent due to the reflexive property of congruence. Therefore, the following elements must be highlighted:
- Side FE is congruent to side GH (given information).
- Angle FHE is congruent to angle GEH (as established earlier).
- Side EH is congruent to side EH (reflexive property).
Step 3: Apply SAS Congruence Criterion
To conclude that triangles FHE and GEH are congruent, we can employ the side-angle-side (SAS) congruence criterion. This criterion states that if two sides and the included angle of one triangle are congruent to the corresponding parts of another triangle, then the triangles are congruent. With the three congruent components identified, we can confidently say that triangles FHE and GEH are congruent, hence proving that ŒiFHE ‚aO ŒiGEH.