Respuesta :
The pattern is add the next odd number. Each time you go up a number, you go up an odd number. That's confusing so let me explain:
1+3=4
4+5=9
9+7=16
16+9=25
25+11=36
36+13=49
49+15=x
so the answer is 64
1+3=4
4+5=9
9+7=16
16+9=25
25+11=36
36+13=49
49+15=x
so the answer is 64