What exspression is equivalent to

For how answer my question this will be the last question can you answer in math subject

Match the following reasons with the statements given to create the proof. 1. do = ob, ao = oc sas 2. doc = aob given 3. triangle cod congruent to triangle aob vertical angles are equal. 4. 1 = 2, ab = dc if two sides = and ||, then a parallelogram. 5. ab||dc if alternate interior angles =, then lines parallel. 6. abcd is a parallelogram cpcte

X^2/100+y^2/25=1 the length of the major axis is: a)5 b)10 c)20