_______ 9,25, 49, 121,169

Options

A. 1
B. 2
C. 3
D. 4

Answer

To find the missing term in the sequence: 9, 25, 49, 121, 169, we will analyze the given numbers step by step.

### Step 1: Identify the pattern in the sequence
The given numbers are:
- 9
- 25
- 49
- 121
- 169

### Step 2: Recognize the squares of prime numbers
Let's find the square roots of these numbers:
- \(9 = 3^2\)
- \(25 = 5^2\)
- \(49 = 7^2\)
- \(121 = 11^2\)
- \(169 = 13^2\)

### Step 3: List the prime numbers
The square roots correspond to the following prime numbers:
- \(3\) (for \(9\))
- \(5\) (for \(25\))
- \(7\) (for \(49\))
- \(11\) (for \(121\))
- \(13\) (for \(169\))

### Step 4: Identify the missing prime number
The prime numbers in order are:
- \(2\)
- \(3\)
- \(5\)
- \(7\)
- \(11\)
- \(13\)

The prime number that comes before \(3\) is \(2\). The square of \(2\) is:
- \(2^2 = 4\)

### Conclusion: Determine the first term
Thus, the first term in the sequence is \(4\).

### Final Answer
The missing term is **4**.

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