An airplane is heading due north at 800 km h when it encounters a wind from the northeast at 100km h, what is the ground velocity  how would we solve this question and what are the steps we need to take 

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