What is x when 45 divided by x equals 4?

To find the answer, just divide the dividend by the quotient: 45 ÷ 4 = 11.25

To prove this, let's compute 45 divided by 11.25: $\frac{45}{11.25} = 4$

How does it work?

Asking what the value of x could be when 45 divided by x gives a result of 4, is equivalent to solving the following equation:

$\frac{45}{x} = 4$

Multiply both sides by x: $\frac{45 x}{x} = 4 x$
$\frac{45 x}{x}$ is equivalent to $\frac{x}{x} \times 45$ , which simplifies to $1 \times 45$ (or just $45$ ).
Thus, the equation becomes: $45 = 4 x$
To find x, divide both sides by 4: $\frac{45}{4} = \frac{4 x}{4}$
Which gives, after simplification: $11.25 = x$ (or $x = 11.25$ )

So, if the dividend is 45 and the quotient is 4, the divisor is 11.25.