Respuesta :
Given: AD ≅ BC and AD ∥ BC
Prove: ABCD is a parallelogram.
Statements Reasons
1. AD ≅ BC; AD ∥ BC 1. given
2. ∠CAD and ∠ACB are alternate interior ∠s 2. definition of alternate interior angles
3. ∠CAD ≅ ∠ACB 3. alternate interior angles are congruent
4. AC ≅ AC 4. reflexive property
5. △CAD ≅ △ACB 5. SAS congruency theorem
6. AB ≅ CD 6. Corresponding Parts of Congruent triangles are Congruent (CPCTC)
7. ABCD is a parallelogram 7. parallelogram side theorem
Given: It is given that [tex]AD \cong BC[/tex] and [tex]AD \parallel BC[/tex].
To Prove: ABCD is a parallelogram.
Statements
1. [tex]AD \cong BC[/tex] and [tex]AD \parallel BC[/tex]
Reason: Given
2. [tex]\angle CAD, \angle ACB[/tex] are alternate interior angles
Reason: Def of alternate interior angles
3. [tex]\angle CAD \cong \angle ACB[/tex]
Reason: Alternate interior angles are congruent
4. [tex]AC \cong AC[/tex]
Reason: Reflexive property
5. [tex]\Delta CAD \cong \Delta ACB[/tex]
Reason: SAS congruency theorem
6. [tex]AB \cong CD[/tex]
Reason: Corresponding Parts of Congruent triangles are Congruent (CPCTC)
7. ABCD is a parallelogram
Reason: Parallelogram Side Theorem