The company XYZ bought property for OMR 600,000 on 1 January 2017. The land element of the purchase was OMR 100,000. The expected life of the building was 30 years and its residual value nil. On 31 December 2019, the property was revalued to OMR 700,000, of which the land element was OMR 124,000 and the building – OMR 576,000. On 31 December 2020, the property was sold for OMR 680,000.

Given: ab ≅ cd and ad ≅ bc prove: abcd is a parallelogram. statements reasons 1. ab ≅ cd; ad ≅ bc 1. given 2. ac ≅ ac 2. reflexive property 3. △adc ≅ △cba 3. ? 4. ∠dac ≅ ∠bca; ∠acd ≅ ∠cab 4. cpctc 5. ∠dac and ∠bca are alt. int. ∠s; ∠acd and ∠cab are alt. int. ∠s 5. definition of alternate interior angles 6. ab ∥ cd; ad ∥ bc 6. converse of the alternate interior angles theorem 7. abcd is a parallelogram 7. definition of parallelogram what is the missing reason in step 3? triangle angle sum theorem sas congruency theorem sss congruency theorem cpctc