QUESTION IMAGE
Question
prove: ( overline{gh} cong overline{eh} ) ( overline{dh} cong overline{fh} ) what is the reason for step 5 in this proof? proof
| statement | reason | --- | --- | 1. quadrilateral defg is a parallelogram. | given | 2. ( overline{de} parallel overline{gf} ) ( overline{dg} parallel overline{ef} ) | definition of a parallelogram | 3. 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 segments | 4. place point h where ( overline{df} ) and ( overline{ge} ) intersect. | defining a point | 5. ( 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 congruence | 8. ( 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
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).
Snap & solve any problem in the app
Get step-by-step solutions on Sovi AI
Photo-based solutions with guided steps
Explore more problems and detailed explanations
D. Alternate Interior Angles Theorem