please help me on these 6 questions about proportions (fill in the black) HELP

Answer:
1. 6
2. 800
3. 10
4. 120
5. 3.5
6. 9
Step-by-step explanation:
I like to cross multiply for these type of problems.
I will show an example:
x/15=2/5 you multiply the opposite terms so 5x=30 then solve so x=6