What is Mean Proportional

What is mean proportion of 4 and 25.

What is the mean proportional of (15+ sqrt200) and (27- sqrt 648)?

What is the mean proportional of 3 + sqrt2 , 12 - sqrt32

What is the mean proportional between (15 + sqrt(200)) and (27-sqrt(648)) ?

What is the mean proportional 3+sqrt(2),12-sqrt(32)

If 12, x, 8 and 14 are in proportion, then what is the mean proportional between (x - 12) and (x + 4)

If x is subtracted from each other of 17, 14, 22 and 18 then these numbers are in proportion, in this order. What is the mean proportion between 9x and 5x?