Answer:
115
Step-by-step explanation:
Consider the sequence of triangles
3, 5, 7
There is a common difference between consecutive terms, that is
d = 7 - 5 = 5 - 3 = 2
This indicates the sequence is arithmetic with n th term
[tex]a_{n}[/tex] = a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Here a₁ = 3 and d = 2, thus
[tex]a_{57}[/tex] = 3 + (56 × 2) = 3 + 112 = 115
