# Complete the series: 11, 29, 55, ?, 131 :

- 81,
- 110
- 78
- 89

**Answer: (4) 89**

**Explanation:-**

The square of 3 + 2 x 1 = 9 + 2 = 11,

The square of 5 + 2 x 2 = 25 + 4 = 29,

The square of 7 + 2 x 3 = 49 + 6 = 55,

**The square of 9 + 2 x 4 = 81 + 8 = 89**

The square of 11 + 2 x 5 = 121 + 10 = 131

Hence, the answer is (4) 89.