Here is the equation:
[tex]\frac{3}{10} = \frac{30}{100} \rightarrow \frac{4}{10} =\frac{x}{100}[/tex]
To find the missing number, you have to cross multiply. Here's the equation:
[tex]\frac{4}{10} = \frac{x}{100} \\ \\ 100 \times 4 = 10x[/tex]
Multiply:
[tex]100 \times 4 = 400 \\ 400 = 10x[/tex]
To leave the variable x alone, you need to divide both sides by 10
[tex]\frac{400}{10} = \frac{10x}{10}[/tex]
Divide:
[tex]400 \div 10 = 40 \\ x = 40[/tex]
Your answer is 40
If you have any questions, feel free to ask in the comments! :)
