Help #3 ​

5.

Note, NSS  ....that we multiplied 50  by the common ratio, r, twice to  get 450

So

50 * r^2   =  450    divide bott sides by  50

r^2  =  9        take the positive root of both sides

r  = 3

So.....the missing term is

50 * r   =    50 * 3   =    150