Each of the capital letters in bold represents a different digit from 0 to 9. None of the numbers can contain a leading zero.

1. TWO is a prime number, and:
2. THREE is a triangular number, and:
3. FOUR is a perfect square.

Determine the numbers represented by:

(i) THREE   (ii) FOUR

*** *** Adapted from Enigma No. 1341 by Richard England appearing in "New Scientist" on May 21, 2005.