Find the missing number ?

Answer is 11 First row is square of second row Second row5*5=25, 7*7=49, therefore 11*11=121 and Second row + third row = fourth row 5+15=20, 7+13=20 and 11+9=20

Answer is 11

The answer is 11

Find the missing number in the following grid?

6, 2, 17, 1, 4, 11, 3, 7, ?

Find the missing no in the following grid -

2 8 9 3 2 4 3 6 ?