Let a & d be the first term & common difference respectively.

S_m : S_n = m² : n²

m/2*[2a + (m - 1)d] : n/2*[2a + (n - 1)d] = m² : n²

2a + (m-1)d : 2a + (n-1)d = m² : n²

Solving we get, d = 2a.

T_m : T_n = a + (m-1)d : a + (n-1)d

= a + 2a(m-1) : a + 2a(n-1)

= 2m - 1 : 2n -1.