The problem asks to find a number that makes the ratio equivalent to 1:4, with the format $\text{?}:28$.

Solution:

We are given the equivalent ratio $1:4$ and asked to find the unknown number in the ratio $\text{?}:28$.

The ratio $1:4$ means that for every 1 unit in the first part, there are 4 units in the second part. This ratio can be expressed as:

$\frac{1}{4} = \frac{x}{28}$

To find $x$, we can use cross-multiplication:

$1 \times 28 = 4 \times x$

$28 = 4x$

Now, solve for $x$:

$x = \frac{28}{4} = 7$

Thus, the number is 7. The equivalent ratio is 7:28.

Would you like more details, or have any further questions?

Here are 5 related questions for practice:

1. What is the equivalent ratio of $2:5$ when the second term is 20?
2. Find the missing number in the ratio $3:? = 6:18$.
3. If the ratio of $5:9$ is scaled up by 3, what is the new ratio?
4. How do you simplify the ratio $14:42$?
5. What is the relationship between proportions and ratios?

Tip: When working with ratios, cross-multiplication is a quick way to solve for unknowns when you have equivalent ratios.