Answer:
SSS congruency theorem ⇒ 3rd answer
Step-by-step explanation:
* Lets revise the cases of congruent
- SSS ⇒ 3 sides in the 1st Δ ≅ 3 sides in the 2nd Δ
- SAS ⇒ 2 sides and including angle in the 1st Δ ≅ 2 sides and
including angle in the 2nd Δ
- ASA ⇒ 2 angles and the side whose joining them in the 1st Δ
≅ 2 angles and the side whose joining them in the 2nd Δ
- AAS ⇒ 2 angles and one side in the first triangle ≅ 2 angles
and one side in the 2ndΔ
- HL ⇒ hypotenuse leg of the first right angle triangle ≅ hypotenuse
leg of the 2nd right angle Δ
* Lets complete the missing
- Given: AB ≅ CD and AD ≅ BC
- Prove: ABCD is a parallelogram
* Statements Reasons
1. AB ≅ CD ; AD ≅ BC given
2. AC ≅ AC reflexive property
3. △ ADC ≅ △ CBA SSS congruency theorem
- The three sides in Δ ADC equal the three sides in ΔCBA,
then the two triangles are congruent by SSS theorem
∴ The missing reason in step 3 is SSS congruency theorem
