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prove: ( overline{gh} cong overline{eh} ) ( overline{dh} cong overline{…

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prove: ( overline{gh} cong overline{eh} ) ( overline{dh} cong overline{fh} ) what is the reason for step 5 in this proof? proof

statementreason------1. quadrilateral defg is a parallelogram.given2. ( overline{de} parallel overline{gf} ) ( overline{dg} parallel overline{ef} )definition of a parallelogram3. draw ( overline{df} ) and ( overline{ge} ). these line segments are transversals cutting two pairs of parallel lines: ( overleftrightarrow{de} ) and ( overleftrightarrow{gf} ) and ( overleftrightarrow{dg} ) and ( overleftrightarrow{ef} ).drawing line segments4. place point h where ( overline{df} ) and ( overline{ge} ) intersect.defining a point5. ( angle hgd cong angle hef ) ( angle hdg cong angle hfe )6. ( overline{dg} cong overline{ef} )opposite sides of a parallelogram are congruent.7.asa criterion for congruence8. ( overline{gh} cong overline{eh} ) ( overline{dh} cong overline{fh} )corresponding sides of congruent triangles are congruent.

a. vertical angles theorem
b. opposite interior angles of a parallelogram are congruent.
c. all angles of a rectangle have the same measure.
d. alternate interior angles theorem

Explanation:

Brief Explanations
  • Vertical Angles Theorem: States that vertical angles (opposite angles formed by two intersecting lines) are congruent. But here we are dealing with angles formed by parallel lines and transversals.
  • Opposite interior angles of a parallelogram are congruent: This is not a standard theorem. The standard ones are about opposite sides and opposite angles (not "interior" in this context).
  • All angles of a rectangle have the same measure: A rectangle is a special case of a parallelogram, but we are not told this is a rectangle. The problem starts with a general parallelogram.
  • Alternate Interior Angles Theorem: When a transversal cuts two parallel lines, alternate - interior angles are congruent. In the proof, since \(DE\parallel GF\) (from the definition of a parallelogram) and \(GE\) is a transversal, \(\angle HGD\cong\angle HEF\) (alternate - interior angles). Also, since \(DG\parallel EF\) (definition of a parallelogram) and \(DF\) is a transversal, \(\angle HDG\cong\angle HFE\) (alternate - interior angles).

Answer:

D. Alternate Interior Angles Theorem