Maths Quiz (Round 2)

[Desgracias]

yayaya its here

The sequel to my previous post on this section. Everything here will be about numerical sequences, such as squares, cubes, triangular numbers, and 4D cubes (n^4). Anyways, here we go!

1. What is the 19th triangular number?
2. 27^2
3. 21^2
4. 7^3
5. What is the 13th triangular number?
6. 29^2
7. 9^4
8. 5^4
9. What is the 16th triangular number?
10. 23^2

You don't have to do all of them at once, and try not to use a calculator. Anyways, good luck! 

From Uli, 11 years old. Thank you for reading.