What is x when 39 divided by x equals 4?

To find the answer, just divide the dividend by the quotient: 39 ÷ 4 = 9.75

To prove this, let's compute 39 divided by 9.75: $\frac{39}{9.75} = 4$

How does it work?

Asking what the value of x could be when 39 divided by x gives a result of 4, is equivalent to solving the following equation:

$\frac{39}{x} = 4$

Multiply both sides by x: $\frac{39 x}{x} = 4 x$
$\frac{39 x}{x}$ is equivalent to $\frac{x}{x} \times 39$ , which simplifies to $1 \times 39$ (or just $39$ ).
Thus, the equation becomes: $39 = 4 x$
To find x, divide both sides by 4: $\frac{39}{4} = \frac{4 x}{4}$
Which gives, after simplification: $9.75 = x$ (or $x = 9.75$ )

So, if the dividend is 39 and the quotient is 4, the divisor is 9.75.