Find the tenth triangular number if the first triangular number is 1 and represent it in a triangular pattern.
Find the next triangular number after 15 and represent it in the triangular pattern.
Find the smallest square number which is also a triangular number, other than 1. Represent it in a triangular pattern as well as in a square-shaped pattern.
Find the difference between the sixth and fifth triangular number if the first triangular number is 1.
The tenth triangular number is ___.