What is the next number in the series? 4, 9, 25, 49, ?

Concept: A squares-of-primes series lists the squares of consecutive prime numbers, in increasing order (22, 32, 52, 72, 112, …); each next term is the square of the prime that comes immediately after the previous base.

1. Identify the pattern: the terms 4, 9, 25, 49 equal 22, 32, 52, 72 — the squares of the primes 2, 3, 5, 7.

2. Find the next prime after 7: checking 8, 9, 10 — 8 = 2 × 4, 9 = 3 × 3, 10 = 2 × 5 — none of these is prime, so the next prime is 11.

3. Square it: 112 = 121.

Cross-check: listing the bases in order — 2, 3, 5, 7, 11 — confirms they are exactly the prime numbers with no gaps or repeats, so 121 is consistent with the pattern established by the series.