Question

If 3/10 = 30/100 than 4/10 = ?/100

Answer 1

I'm pretty sure 4/10=40/100

Answer 2

Here is the equation:

$\frac{3}{10} = \frac{30}{100} \rightarrow \frac{4}{10} =\frac{x}{100}$

To find the missing number, you have to cross multiply. Here's the equation:

$\frac{4}{10} = \frac{x}{100} \\ \\ 100 \times 4 = 10x$

Multiply:

$100 \times 4 = 400 \\ 400 = 10x$

To leave the variable x alone, you need to divide both sides by 10

$\frac{400}{10} = \frac{10x}{10}$

Divide:

$400 \div 10 = 40 \\ x = 40$

Your answer is 40

If you have any questions, feel free to ask in the comments! :)