Three numbers form a g. p. if the first and third numbers are 5and245 respectively, find two possible values for the middle number.

A geometric progression is when you have a common ratio. In order for 3 numbers (5, x and 245) to be a geometric progression they should have a common ratio. In order to solve the 2nd number the common ration should be establish; (x/5) = (245/x) solving for x, the middle number is either 35 or - 35.