11,17,18,19,23,21,14 what is the median

Typically a point in a three dimensional cartesian coordinate system is represented by which of the following answers in the picture !

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

What are the angle measures in triangle abc? m∠a = 90°,  m∠b = 30°,  m∠c = 60°m∠a = 60°,  m∠b = 90°,  m∠c = 30°m∠a = 90°,  m∠b = 60°,  m∠c = 30°m∠a = 60°,  m∠b = 30°,  m∠c = 90°