I don't have the time to sort them out for you, sadly, but, I can provide you with some steps for each.
1) That can only be solved with the Pythagorean theorem :
![x {}^(2) = 8 {}^(2) + 15 {}^(2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/z9ru0dfnx6ixgqtq9xdksqxffqrnfcm85l.png)
2) That also looks like it can be simplified with the Pythagorean theorem.
3) The unknown side with the "\" on it is equal to
![8 √(2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/mwa423qpp3j13y7oqajr1qoozrd556g9er.png)
then it can be simplified massively with the Pythagorean theorem.
4) Since that triangle's total is 180°, and since we know that one side is 90°, the other two (assuming they're equal) have to be 45°, respectively. Knowing that you can find
![\sin(45)](https://img.qammunity.org/2021/formulas/mathematics/high-school/xpaauza2q0ucy8qgvrbo229v4gc86nag1n.png)
then, all you have to do is find x (see below for more details)
5) to find x, you can first find
![\cos(60)](https://img.qammunity.org/2021/formulas/mathematics/high-school/kxpb9c2an5awvexddjbphjr6p2zok7i9zf.png)
and then find x: (done similarly with triangle 4)
![\cos(60) = (x)/( 4√(3))](https://img.qammunity.org/2021/formulas/mathematics/high-school/xox4cd9xienla7eghc6xfhsodah4yse5ct.png)
Just gonna leave the rest for you. Have a nice day!