Ineed with question number three and four !

Which expresions are equivalent to the one below? check all that apply. 5x

Determine the common ratio and find the next three terms of the geometric sequence. 10, 2, 0.4, a. 0.2; -0.4, -2, -10 c. 0.02; 0.08, 0.016, 0.0032 b. 0.02; -0.4, -2, -10 d. 0.2; 0.08, 0.016, 0.0032 select the best answer from the choices provided a b c d

Cd is the perpendicular bisector of both xy and st, and cy=20. find xy.